[range.repeat.view] Add \libconcept for same_as (#5764)

Author: hewillk

source/ranges.tex

@@ -3527,7 +3527,7 @@
 
 \indexlibrarymember{size}{repeat_view}%
 \begin{itemdecl}
-constexpr auto size() const requires (!same_as<Bound, unreachable_sentinel_t>);
+constexpr auto size() const requires (!@\libconcept{same_as}@<Bound, unreachable_sentinel_t>);
 \end{itemdecl}
 
 \begin{itemdescr}