updated for version 7.4.314
Problem:    Completion messages can get in the way of a plugin.
Solution:   Add 'c' flag to 'shortmess' option. (Shougo Matsu)
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 7c772df..f2e6e66 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -6254,6 +6254,9 @@
 	  A	don't give the "ATTENTION" message when an existing swap file
 		is found.
 	  I	don't give the intro message when starting Vim |:intro|.
+	  c	don't give |ins-completion-menu| messages.  For example,
+		"-- XXX completion (YYY)", "match 1 of 2", "The only match",
+		"Pattern not found", "Back at original", etc.
 
 	This gives you the opportunity to avoid that a change between buffers
 	requires you to hit <Enter>, but still gives as useful a message as