Improve issue wording after feedback from submitter

xml/issue3976.xml

@@ -26,7 +26,7 @@ sentence, such as an <tt>allocator_type</tt> member. Perhaps we want to say a co
 type <tt>X</tt> is allocator-aware using allocator <tt>A</tt> if [&hellip;], and then that <tt>basic_string</tt> and
 containers that are not otherwise allocator aware are are treated as-if they were
 allocator-aware using <tt>std::allocator&lt;typename X::value_type&gt;</tt> (where <tt>value_type</tt>
-is already guaranteed to exist by the basic container requirements).
+is already guaranteed to exist by the <i>container</i> requirements, <sref ref="[container.reqmts]"/> p1).
 </p>
 </discussion>