[mdspan.sub.map.rightpad] Add missing \exposid around "submdspan-mapping-impl"

Author: eisenwave

source/containers.tex

@@ -25931,7 +25931,7 @@
 \begin{itemdecl}
 template<class Extents>
 template<class... SliceSpecifiers>
-constexpr auto layout_right_padded::mapping<Extents>::submdspan-mapping-impl(
+constexpr auto layout_right_padded::mapping<Extents>::@\exposid{submdspan-mapping-impl}@(
     SliceSpecifiers... slices) const -> @\seebelow@;
 \end{itemdecl}