P2787R1 pmr::generator - Promise Types are not Values

Fixes NB US 116 (C++23 CD).

Author: jensmaurer

source/ranges.tex

@@ -15737,6 +15737,11 @@
   // \ref{coro.generator.class}, class template \tcode{generator}
   template<class Ref, class V = void, class Allocator = void>
     class generator;
+
+  namespace pmr {
+    template<class R, class V = void>
+      using generator = std::generator<R, V, polymorphic_allocator<>>;
+  }
 }
 \end{codeblock}