[container.alloc.reqmts] End note with period (#6787)

Author: Andreas-Krug

source/containers.tex

@@ -958,7 +958,7 @@
 and its evaluation causes the following postcondition to hold: The value
 of \tcode{*p} is equivalent to the value of \tcode{rv} before the evaluation.
 \begin{note}
-\tcode{rv} remains a valid object. Its state is unspecified
+\tcode{rv} remains a valid object. Its state is unspecified.
 \end{note}
 
 \item