[functional.syn] Move variable templates next to traits. (#3536)

Author: brycelelbach

source/utilities.tex

@@ -13537,7 +13537,11 @@
 
   // \ref{func.bind}, bind
   template<class T> struct is_bind_expression;
+  template<class T>
+    inline constexpr bool @\libglobal{is_bind_expression_v}@ = is_bind_expression<T>::value;
   template<class T> struct is_placeholder;
+  template<class T>
+    inline constexpr int @\libglobal{is_placeholder_v}@ = is_placeholder<T>::value;
 
   template<class F, class... BoundArgs>
     constexpr @\unspec@ bind(F&&, BoundArgs&&...);
@@ -13588,12 +13592,6 @@
   template<class T>
     struct hash;
 
-  // \ref{func.bind}, function object binders
-  template<class T>
-    inline constexpr bool @\libglobal{is_bind_expression_v}@ = is_bind_expression<T>::value;
-  template<class T>
-    inline constexpr int @\libglobal{is_placeholder_v}@ = is_placeholder<T>::value;
-
   namespace ranges {
     // \ref{range.cmp}, concept-constrained comparisons
     struct equal_to;