patch 9.1.0010: Keymap completion is not available

Problem:  Keymap completion is not available
Solution: Add keymap completion (Doug Kearns)

Add keymap completion to the 'keymap' option, user commands and builtin
completion functions.

closes: #13692

Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index 33ff606..4554712 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -545,6 +545,13 @@
   let l = getcompletion('horse', 'filetype')
   call assert_equal([], l)
 
+  if has('keymap')
+    let l = getcompletion('acc', 'keymap')
+    call assert_true(index(l, 'accents') >= 0)
+    let l = getcompletion('nullkeymap', 'keymap')
+    call assert_equal([], l)
+  endif
+
   let l = getcompletion('z', 'syntax')
   call assert_true(index(l, 'zimbu') >= 0)
   let l = getcompletion('emacs', 'syntax')