completion: add more cherry-pick options

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/completion/git-completion.bash

@@ -1124,9 +1124,14 @@ _git_cherry ()
 
 _git_cherry_pick ()
 {
+	local dir="$(__gitdir)"
+	if [ -f "$dir"/CHERRY_PICK_HEAD ]; then
+		__gitcomp "--continue --quit --abort"
+		return
+	fi
 	case "$cur" in
 	--*)
-		__gitcomp "--edit --no-commit"
+		__gitcomp "--edit --no-commit --signoff --strategy= --mainline"
 		;;
 	*)
 		__gitcomp_nl "$(__git_refs)"