[hive.overview] Add/fix missing subject "insertion"

Author: tkoeppe

source/containers.tex

@@ -7931,7 +7931,7 @@
 that provides constant-time insertion and erasure operations.
 Storage is automatically managed in multiple memory blocks,
 referred to as \defnx{element blocks}{element block}.
-Insertion position is determined by the container, and
+Insertion position is determined by the container, and insertion
 may re-use the memory locations of erased elements.
 
 \pnum