[over.call.func] Add period to end of sentence

Author: Andreas-Krug

source/overloading.tex

@@ -457,7 +457,7 @@
 
 \pnum
 In unqualified function calls, the function is designated by
-an \grammarterm{id-expression} or a \grammarterm{splice-expression} $E$
+an \grammarterm{id-expression} or a \grammarterm{splice-expression} $E$.
 The set of candidate functions either
 is the set found by name lookup\iref{basic.lookup}
 if $E$ is an \grammarterm{id-expression} or