[map.overview] Fix punctuation (cplusplus#7677)

Author: Andreas-Krug

source/containers.tex

@@ -10275,7 +10275,7 @@
 A \tcode{map} meets all of the requirements of
 a container\iref{container.reqmts},
 of a reversible container\iref{container.rev.reqmts},
-of an allocator-aware container\iref{container.alloc.reqmts}. and
+of an allocator-aware container\iref{container.alloc.reqmts}, and
 of an associative container\iref{associative.reqmts}.
 A
 \tcode{map}