[utility.underlying] Add to_underlying to index (cplusplus#4578)

hanickadot · web-flow · commit 87ac40a28863 · 2021-04-06T09:09:22.000+02:00
diff --git a/source/utilities.tex b/source/utilities.tex
@@ -574,6 +574,7 @@
 
 \rSec2[utility.underlying]{Function template \tcode{to_underlying}}
 
+\indexlibraryglobal{to_underlying}%
 \begin{itemdecl}
 template<class T>
   constexpr underlying_type_t<T> to_underlying(T value) noexcept;
