[range.take.while.sentinel] Add missing template parameter (#3604)

Also add a cross-reference for the declaration of sentinel in [range.take.while].

source/ranges.tex

@@ -4333,6 +4333,7 @@
   requires input_range<V> && is_object_v<Pred> &&
     indirect_unary_predicate<const Pred, iterator_t<V>>
   class take_while_view : public view_interface<take_while_view<V, Pred>> {
+    // \ref{range.take.while.sentinel}, class template \tcode{take_while_view::\exposid{sentinel}}
     template<bool> class @\exposid{sentinel}@;                      // \expos
 
     V @\exposid{base_}@;                                            // \expos
@@ -4393,9 +4394,9 @@
 \indexlibraryglobal{take_while_view::sentinel}%
 \begin{codeblock}
 namespace std::ranges {
-  template<class V>
+  template<class V, class Pred>
   template<bool Const>
-  class take_while_view<V>::@\exposid{sentinel}@ {                  // \expos
+  class take_while_view<V, Pred>::@\exposid{sentinel}@ {            // \expos
     using @\exposid{base-t}@ = conditional_t<Const, const V, V>;    // \expos
 
     sentinel_t<@\exposid{base-t}@> @\exposid{end_}@ = sentinel_t<@\exposid{base-t}@>();     // \expos