[move.iter.elem] Add missing 'return'

Author: Patrick Palka

source/iterators.tex

@@ -4251,7 +4251,7 @@
 \begin{itemdescr}
 \pnum
 \effects
-Equivalent to: \tcode{ranges::iter_move(current + n);}
+Equivalent to: \tcode{return ranges::iter_move(current + n);}
 \end{itemdescr}
 
 \rSec3[move.iter.nav]{Navigation}