added comment about vault multifile

CHANGELOG.md

@@ -185,6 +185,7 @@ Minor changes:
  * play output is now dynamically sized to terminal with a minimal of 80 coluumns (old default)
  * vars_prompt and pause are now skipped with a warning if the play is called non interactively (i.e. pull from cron)
  * Support for OpenBSD's 'doas' privilege escalation method.
+ * most vault operations can now be done over multilple files
 
 ## 1.9.2 "Dancing In the Street" - Jun 26, 2015