[inplace.vector.erasure] Added missing return statement

Author: hewillk

source/containers.tex

@@ -10142,6 +10142,7 @@
 auto it = remove_if(c.begin(), c.end(), pred);
 auto r = distance(it, c.end());
 c.erase(it, c.end());
+return r;
 \end{codeblock}
 \end{itemdescr}