[range.elements.iterator] Add missing \exposid formatting

Author: jensmaurer

source/ranges.tex

@@ -8365,7 +8365,7 @@
 \begin{itemdescr}
 \pnum
 \effects
-Equivalent to: \tcode{return iterator\{x\} += y;}
+Equivalent to: \tcode{return \exposid{iterator}\{x\} += y;}
 \end{itemdescr}
 
 \indexlibrarymember{operator+}{elements_view::iterator}%
@@ -8389,7 +8389,7 @@
 \begin{itemdescr}
 \pnum
 \effects
-Equivalent to: \tcode{return iterator\{x\} -= y;}
+Equivalent to: \tcode{return \exposid{iterator}\{x\} -= y;}
 \end{itemdescr}
 
 \indexlibrarymember{operator-}{elements_view::iterator}%