[mdspan.layout.leftpad.overview, mdspan.layout.rightpad.overview] Add \exposid for rank_ and extents_ (cplusplus#8949)

Author: hewillk

source/containers.tex

@@ -23245,7 +23245,7 @@
 
     // \ref{mdspan.layout.leftpad.obs}, observers
     constexpr const extents_type& extents() const noexcept { return @\exposid{extents_}@; }
-    constexpr array<index_type, rank_> strides() const noexcept;
+    constexpr array<index_type, @\exposid{rank_}@> strides() const noexcept;
 
     constexpr index_type required_span_size() const noexcept;
     template<class... Indices>
@@ -23881,8 +23881,8 @@
     constexpr mapping& operator=(const mapping&) noexcept = default;
 
     // \ref{mdspan.layout.rightpad.obs}, observers
-    constexpr const extents_type& extents() const noexcept { return extents_; }
-    constexpr array<index_type, rank_> strides() const noexcept;
+    constexpr const extents_type& extents() const noexcept { return @\exposid{extents_}@; }
+    constexpr array<index_type, @\exposid{rank_}@> strides() const noexcept;
 
     constexpr index_type required_span_size() const noexcept;