[reverse.iter.elem,reverse.iter.nav] Insert spaces around operators for consistency

Author: Andreas-Krug

source/iterators.tex

@@ -3410,7 +3410,7 @@
 \begin{itemdescr}
 \pnum
 \returns
-\tcode{current[-n-1]}.
+\tcode{current[-n - 1]}.
 \end{itemdescr}
 
 \rSec3[reverse.iter.nav]{Navigation}
@@ -3423,7 +3423,7 @@
 \begin{itemdescr}
 \pnum
 \returns
-\tcode{reverse_iterator(current-n)}.
+\tcode{reverse_iterator(current - n)}.
 \end{itemdescr}
 
 \indexlibrarymember{operator-}{reverse_iterator}%
@@ -3434,7 +3434,7 @@
 \begin{itemdescr}
 \pnum
 \returns
-\tcode{reverse_iterator(current+n)}.
+\tcode{reverse_iterator(current + n)}.
 \end{itemdescr}
 
 \indexlibrarymember{operator++}{reverse_iterator}%