[alg.find.first.of,alg.search,alg.unique] Insert spaces around operators for consistency (#7584)

Author: Andreas-Krug

source/algorithms.tex

@@ -4113,7 +4113,7 @@
 
 \pnum
 \complexity
-At most \tcode{(last1-first1) * (last2-first2)} applications
+At most \tcode{(last1 - first1) * (last2 - first2)} applications
 of the corresponding predicate and any projections.
 \end{itemdescr}
 
@@ -4606,7 +4606,7 @@
 \begin{itemdescr}
 \pnum
 \returns
-The first iterator \tcode{i} in the range \range{first1}{last1 - (last2-first2)}
+The first iterator \tcode{i} in the range \range{first1}{last1 - (last2 - first2)}
 such that
 for every non-negative integer \tcode{n} less than \tcode{last2 - first2}
 the following corresponding conditions hold:
@@ -4705,7 +4705,7 @@
 
 \pnum
 \returns
-The first iterator \tcode{i} in the range \range{first}{last-count}
+The first iterator \tcode{i} in the range \range{first}{last - count}
 such that for every non-negative integer \tcode{n} less than \tcode{count}
 the condition $E$ is true.
 Returns \tcode{last} if no such iterator is found.
@@ -6260,7 +6260,7 @@
 \expects
 \begin{itemize}
 \item
-  The ranges \range{first}{last} and \range{result}{result+(last-first)}
+  The ranges \range{first}{last} and \range{result}{result + (last - first)}
   do not overlap.
 \item
   For the overloads in namespace \tcode{std}: