Optimize links in README + spelling

.codespellrc

@@ -1,3 +1,3 @@
 [codespell]
-skip = ./third_party/simde,./.git,./benchmark/python,./experiments
+skip = ./third_party/simde,./.git,./benchmark/python,./experiments,./gh-pages,./build
 ignore-words-list=shft

README.md

@@ -2,18 +2,18 @@
 High Performance Combinatorics in C++ using vector instructions v0.0.8
 
 HPCombi is a C++17 header-only library using the SSE and AVX instruction sets,
-and some equivalents, for very fast manipulation of combinatorial
-objects such as transformations, permutations, and boolean matrices of small
-size. The goal of this project is to implement various new algorithms and
-benchmark them on various compiler and architectures.
+and some equivalents, for very fast manipulation of combinatorial objects such
+as transformations, permutations, and boolean matrices of small size. The goal
+of this project is to implement various new algorithms and benchmark them on
+various compiler and architectures.
 
 HPCombi was initially designed using the SSE and AVX instruction sets, and did
 not work on machines without these instructions (such as ARM). From v1.0.0
-HPCombi supports processors with other instruction sets also, via
-[simd-everywhere](https://github.com/simd-everywhere/simde). It might be the
-case that the greatest performance gains are achieved on processors supporting
-the SSE and AVX instruction sets, but the HPCombi benchmarks indicate that
-there are also still signficant gains on other processors too.
+HPCombi supports processors with other instruction sets also, via [SIMD
+Everywhere][]. It might be the case that the greatest performance gains are
+achieved on processors supporting the SSE and AVX instruction sets, but the
+HPCombi benchmarks indicate that there are also still significant gains on
+other processors too.
 <!-- TODO add link to HPCombi wiki with benchmark graphs -->
 
 ## Authors
@@ -29,10 +29,12 @@ there are also still signficant gains on other processors too.
 
 ## Thanks
 
-- The development of HPCombi was partly funded by the
-  [OpenDreamKit](http://opendreamkit.org/) Horizon 2020 European Research
-  Infrastructure project (#676541), which the authors acknowledge with thanks.
-- Thanks also to the
-  [simd-everywhere](https://github.com/simd-everywhere/simde) and
-  [catch2](https://github.com/catchorg/Catch2) authors and contributors for
-  their excellent libraries!
+- The development of HPCombi was partly funded by the [OpenDreamKit][] Horizon
+  2020 European Research Infrastructure project (#676541), which the authors
+  acknowledge with thanks.
+- Thanks also to the [SIMD everywhere][] and [catch2][] authors and
+  contributors for their excellent libraries!
+
+[SIMD everywhere]: https://github.com/simd-everywhere/simde
+[OpenDreamKit]: https://opendreamkit.org/
+[catch2]: https://github.com/catchorg/Catch2