From 484d7f86734b37eec45f49832a9297c5bd78a528 Mon Sep 17 00:00:00 2001
From: Joseph Edwards <josephdavidedwards@gmail.com>
Date: Tue, 1 Oct 2024 18:32:51 +0100
Subject: [PATCH] Fix doc spacing

---
 include/libsemigroups/ukkonen.hpp | 138 +++++++++++++++++-------------
 1 file changed, 79 insertions(+), 59 deletions(-)

diff --git a/include/libsemigroups/ukkonen.hpp b/include/libsemigroups/ukkonen.hpp
index 7556c9c29..1e376e15a 100644
--- a/include/libsemigroups/ukkonen.hpp
+++ b/include/libsemigroups/ukkonen.hpp
@@ -1143,7 +1143,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w)`
     //! throws for any `w` in \p words.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     void add_words(Ukkonen& u, std::vector<word_type> const& words);
 
     //! \brief Add all words in a range to a Ukkonen object.
@@ -1153,7 +1153,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w)`
     //! throws for any `w` in `[first, last)`.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Iterator1, typename Iterator2>
     void add_words(Ukkonen& u, Iterator1 first, Iterator2 last) {
       for (auto it = first; it != last; ++it) {
@@ -1190,7 +1190,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.cbegin(),  w.cend())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Word>
     auto traverse(Ukkonen const& u, Word const& w) {
       return u.traverse(w.cbegin(), w.cend());
@@ -1203,7 +1203,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.cbegin(),  w.cend())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline auto traverse(Ukkonen const& u, word_type const& w) {
       return u.traverse(w.cbegin(), w.cend());
     }
@@ -1215,66 +1215,86 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w,  w +
     //! std::strlen(w))` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline auto traverse(Ukkonen const& u, char const* w) {
       return u.traverse(w, w + std::strlen(w));
     }
 
-    //! \brief \copybrief Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator, Iterator) const
+    //! \brief \copybrief Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator,
+    //! Iterator) const
     //!
-    //! See \ref Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator, Iterator) const.
+    //! See \ref Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator,
+    //! Iterator) const.
     template <typename Word>
-    auto traverse_no_checks(Ukkonen::State& st, Ukkonen const& u, Word const& w) {
+    auto traverse_no_checks(Ukkonen::State& st,
+                            Ukkonen const&  u,
+                            Word const&     w) {
       return u.traverse_no_checks(st, w.cbegin(), w.cend());
     }
 
-    //! \brief \copybrief Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator, Iterator) const
+    //! \brief \copybrief Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator,
+    //! Iterator) const
     //!
-    //! See \ref Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator, Iterator) const.
-    inline auto traverse_no_checks(Ukkonen::State& st, Ukkonen const& u, word_type const& w) {
+    //! See \ref Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator,
+    //! Iterator) const.
+    inline auto traverse_no_checks(Ukkonen::State&  st,
+                                   Ukkonen const&   u,
+                                   word_type const& w) {
       return u.traverse_no_checks(st, w.cbegin(), w.cend());
     }
 
-    //! \brief \copybrief Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator, Iterator) const
+    //! \brief \copybrief Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator,
+    //! Iterator) const
     //!
-    //! See \ref Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator, Iterator) const.
-    inline auto traverse_no_checks(Ukkonen::State& st, Ukkonen const& u, char const* w) {
+    //! See \ref Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator,
+    //! Iterator) const.
+    inline auto traverse_no_checks(Ukkonen::State& st,
+                                   Ukkonen const&  u,
+                                   char const*     w) {
       return u.traverse_no_checks(st, w, w + std::strlen(w));
     }
 
-    //! \brief \copybrief Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator, Iterator) const
+    //! \brief \copybrief Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator,
+    //! Iterator) const
     //!
-    //! See \ref Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator, Iterator) const.
+    //! See \ref Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator,
+    //! Iterator) const.
     //!
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.cbegin(),  w.cend())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Word>
     auto traverse(Ukkonen::State& st, Ukkonen const& u, Word const& w) {
       return u.traverse(st, w.cbegin(), w.cend());
     }
 
-    //! \brief \copybrief Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator, Iterator) const
+    //! \brief \copybrief Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator,
+    //! Iterator) const
     //!
-    //! See \ref Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator, Iterator) const.
+    //! See \ref Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator,
+    //! Iterator) const.
     //!
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.cbegin(),  w.cend())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
-    inline auto traverse(Ukkonen::State& st, Ukkonen const& u, word_type const& w) {
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
+    inline auto traverse(Ukkonen::State&  st,
+                         Ukkonen const&   u,
+                         word_type const& w) {
       return u.traverse(st, w.cbegin(), w.cend());
     }
 
-    //! \brief \copybrief Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator, Iterator) const
+    //! \brief \copybrief Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator,
+    //! Iterator) const
     //!
-    //! See \ref Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator, Iterator) const.
+    //! See \ref Ukkonen::traverse_no_checks(Ukkonen::State&, Iterator,
+    //! Iterator) const.
     //!
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w,  w +
     //! std::strlen(w))` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline auto traverse(Ukkonen::State& st, Ukkonen const& u, char const* w) {
       return u.traverse(st, w, w + std::strlen(w));
     }
@@ -1338,7 +1358,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(first,
     //! last)` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Iterator>
     bool is_subword(Ukkonen const& u, Iterator first, Iterator last) {
       u.throw_if_not_unique_letters(first, last);
@@ -1353,7 +1373,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.cbegin(), w.cend())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Word>
     bool is_subword(Ukkonen const& u, Word const& w) {
       return is_subword(u, w.cbegin(), w.cend());
@@ -1367,7 +1387,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w,  w +
     //! std::strlen(w))` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline bool is_subword(Ukkonen const& u, char const* w) {
       return is_subword(u, w, w + std::strlen(w));
     }
@@ -1380,7 +1400,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w)`
     //! throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline bool is_subword(Ukkonen const& u, word_type const& w) {
       return is_subword(u, w.cbegin(), w.cend());
     }
@@ -1447,7 +1467,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(first,
     //! last)` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Iterator>
     bool is_suffix(Ukkonen const& u, Iterator first, Iterator last) {
       u.throw_if_not_unique_letters(first, last);
@@ -1462,7 +1482,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.begin(), w.end())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Word>
     bool is_suffix(Ukkonen const& u, Word const& w) {
       return is_suffix(u, w.cbegin(), w.cend());
@@ -1476,7 +1496,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w)`
     //! throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     // This function is required so that we can use initialiser list, as an
     // argument to is_suffix
     inline bool is_suffix(Ukkonen const& u, word_type const& w) {
@@ -1491,7 +1511,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w, w +
     //! std::strlen(w))` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline bool is_suffix(Ukkonen const& u, char const* w) {
       return is_suffix(u, w, w + std::strlen(w));
     }
@@ -1567,7 +1587,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(first,
     //! last)` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Iterator>
     Iterator maximal_piece_prefix(Ukkonen const& u,
                                   Iterator       first,
@@ -1585,7 +1605,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.cbegin(), w.cend())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Word>
     typename Word::const_iterator maximal_piece_prefix(Ukkonen const& u,
                                                        Word const&    w) {
@@ -1601,7 +1621,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w)`
     //! throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline typename word_type::const_iterator
     maximal_piece_prefix(Ukkonen const& u, word_type const& w) {
       return maximal_piece_prefix(u, w.cbegin(), w.cend());
@@ -1616,7 +1636,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w, w +
     //! std::strlen(w))` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline char const* maximal_piece_prefix(Ukkonen const& u, char const* w) {
       return maximal_piece_prefix(u, w, w + std::strlen(w));
     }
@@ -1694,7 +1714,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(first,
     //! last)` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Iterator>
     size_t length_maximal_piece_prefix(Ukkonen const& u,
                                        Iterator       first,
@@ -1711,7 +1731,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.cbegin(), w.cend())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Word>
     size_t length_maximal_piece_prefix(Ukkonen const& u, Word const& w) {
       return length_maximal_piece_prefix(u, w.cbegin(), w.cend());
@@ -1726,7 +1746,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w)`
     //! throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline size_t length_maximal_piece_prefix(Ukkonen const&   u,
                                               word_type const& w) {
       return length_maximal_piece_prefix(u, w.cbegin(), w.cend());
@@ -1741,7 +1761,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w, w +
     //! std::strlen(w))` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline size_t length_maximal_piece_prefix(Ukkonen const& u, char const* w) {
       return length_maximal_piece_prefix(u, w, w + std::strlen(w));
     }
@@ -1804,7 +1824,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(first,
     //! last)` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Iterator>
     bool is_piece(Ukkonen const& u, Iterator first, Iterator last) {
       return maximal_piece_prefix(u, first, last) == last;
@@ -1817,7 +1837,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.cbegin(), w.cend())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Word>
     bool is_piece(Ukkonen const& u, Word const& w) {
       return is_piece(u, w.cbegin(), w.cend());
@@ -1830,7 +1850,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w)`
     //! throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline bool is_piece(Ukkonen const& u, word_type const& w) {
       return is_piece(u, w.cbegin(), w.cend());
     }
@@ -1842,7 +1862,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w, w +
     //! std::strlen(w))` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline bool is_piece(Ukkonen const& u, char const* w) {
       return is_piece(u, w, w + std::strlen(w));
     }
@@ -1920,7 +1940,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(first,
     //! last)` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Iterator>
     Iterator maximal_piece_suffix(Ukkonen const& u,
                                   Iterator       first,
@@ -1938,7 +1958,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.cbegin(), w.cend())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Word>
     typename Word::const_iterator maximal_piece_suffix(Ukkonen const& u,
                                                        Word const&    w) {
@@ -1954,7 +1974,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w)`
     //! throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline typename word_type::const_iterator
     maximal_piece_suffix(Ukkonen const& u, word_type const& w) {
       return maximal_piece_suffix(u, w.cbegin(), w.cend());
@@ -1969,7 +1989,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w, w +
     //! std::strlen(w))` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline char const* maximal_piece_suffix(Ukkonen const& u, char const* w) {
       return maximal_piece_suffix(u, w, w + std::strlen(w));
     }
@@ -2047,7 +2067,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(first,
     //! last)` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Iterator>
     size_t length_maximal_piece_suffix(Ukkonen const& u,
                                        Iterator       first,
@@ -2064,7 +2084,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.cbegin(), w.cend())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Word>
     size_t length_maximal_piece_suffix(Ukkonen const& u, Word const& w) {
       return length_maximal_piece_suffix(u, w.cbegin(), w.cend());
@@ -2079,7 +2099,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w)`
     //! throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline size_t length_maximal_piece_suffix(Ukkonen const&   u,
                                               word_type const& w) {
       return length_maximal_piece_suffix(u, w.cbegin(), w.cend());
@@ -2094,7 +2114,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w, w +
     //! std::strlen(w))` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline size_t length_maximal_piece_suffix(Ukkonen const& u, char const* w) {
       return length_maximal_piece_suffix(u, w, w + std::strlen(w));
     }
@@ -2167,7 +2187,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(first,
     //! last)` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Iterator>
     size_t number_of_pieces(Ukkonen const& u, Iterator first, Iterator last) {
       u.throw_if_not_unique_letters(first, last);
@@ -2183,7 +2203,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.cbegin(), w.cend())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Word>
     size_t number_of_pieces(Ukkonen const& u, Word const& w) {
       return number_of_pieces(u, w.cbegin(), w.cend());
@@ -2198,7 +2218,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w)`
     //! throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline size_t number_of_pieces(Ukkonen const& u, word_type const& w) {
       return number_of_pieces(u, w.cbegin(), w.cend());
     }
@@ -2212,7 +2232,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w, w +
     //! std::strlen(w))` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline size_t number_of_pieces(Ukkonen const& u, char const* w) {
       return number_of_pieces(u, w, w + std::strlen(w));
     }
@@ -2290,7 +2310,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(first,
     //! last)` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Iterator>
     std::vector<Iterator> pieces(Ukkonen const& u,
                                  Iterator       first,
@@ -2306,7 +2326,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if
     //! `u.throw_if_not_unique_letters(w.cbegin(), w.cend())` throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     template <typename Word>
     std::vector<Word> pieces(Ukkonen const& u, Word const& w) {
       u.throw_if_not_unique_letters(w.cbegin(), w.cend());
@@ -2320,7 +2340,7 @@ namespace libsemigroups {
     //! \throws LibsemigroupsException if `u.throw_if_not_unique_letters(w)`
     //! throws.
     //!
-    //!\sa \ref Ukkonen::throw_if_not_unique_letters.
+    //! \sa \ref Ukkonen::throw_if_not_unique_letters.
     inline std::vector<word_type> pieces(Ukkonen const& u, word_type const& w) {
       u.throw_if_not_unique_letters(w);
       return pieces_no_checks(u, w);