[simd.syn] Add simd-iterator to header synopsis

Author: tkoeppe

source/numerics.tex

@@ -16509,6 +16509,10 @@
   template<size_t N> requires (has_single_bit(N))
     constexpr flags<@\exposid{overaligned-flag}<N>@> flag_overaligned{};
 
+  // \ref{simd.iterator}, Class template \exposid{simd-iterator}
+  template<class V>
+    class @\exposidnc{simd-iterator}@;                // \expos
+
   // \ref{simd.class}, Class template \tcode{basic_simd}
   template<class T, class Abi = @\exposid{native-abi}@<T>> class basic_simd;
   template<class T, @\exposid{simd-size-type}@ N = @\exposid{simd-size-v}@<T, @\exposid{native-abi}@<T>>>
@@ -17204,7 +17208,7 @@
   specialization \tcode{\exposid{overaligned-flag}<std::min(N1, N2)>}.
 \end{itemdescr}
 
-\rSec2[simd.iterator]{Class \exposid{simd-iterator}}
+\rSec2[simd.iterator]{Class template \exposid{simd-iterator}}
 \begin{codeblock}
 namespace std::datapar {
   template<class V>