patch 8.0.0034
Problem: No completion for ":messages".
Solution: Complete "clear" argument. (Hirohito Higashi)
diff --git a/runtime/doc/map.txt b/runtime/doc/map.txt
index 7989d64..25ed827 100644
--- a/runtime/doc/map.txt
+++ b/runtime/doc/map.txt
@@ -1280,6 +1280,7 @@
-complete=locale locale names (as output of locale -a)
-complete=mapping mapping name
-complete=menu menus
+ -complete=messages |:messages| suboptions
-complete=option options
-complete=packadd optional package |pack-add| names
-complete=shellcmd Shell command