[refwrap.invoke] Place period at end (#7402)

Author: Andreas-Krug

source/utilities.tex

@@ -11219,7 +11219,7 @@
 
 \pnum
 \returns
-\tcode{\placeholdernc{INVOKE}(get(), std::forward<ArgTypes>(args)...)}.\iref{func.require}
+\tcode{\placeholdernc{INVOKE}(get(), std::forward<ArgTypes>(args)...)}\iref{func.require}.
 \end{itemdescr}
 
 \rSec3[refwrap.comparisons]{Comparisons}