Merge branch 'ac/complete-pull-autostash'

The shell completion (in contrib/) learned that "git pull" can take
the "--autostash" option.

* ac/complete-pull-autostash:
  completion: add --autostash and --no-autostash to pull

contrib/completion/git-completion.bash

@@ -1922,6 +1922,7 @@ _git_pull ()
 	--*)
 		__gitcomp "
 			--rebase --no-rebase
+			--autostash --no-autostash
 			$__git_merge_options
 			$__git_fetch_options
 		"