[concept.comparisoncommontype] Add period to end of sentence

Author: Andreas-Krug

source/concepts.tex

@@ -1033,7 +1033,7 @@
 \item
 \tcode{\exposid{CONVERT_TO_LVALUE}<C>(u1)} equals
 \tcode{\exposid{CONVERT_TO_LVALUE}<C>(u2)}
-if and only if \tcode{u1} equals \tcode{u2}
+if and only if \tcode{u1} equals \tcode{u2}.
 \end{itemize}
 
 \rSec2[concept.equalitycomparable]{Concept \cname{equality_comparable}}