Add bash completion for `plugin disable --force`

Signed-off-by: Harald Albers <github@albersweb.de>
(cherry picked from commit e1403453f0a173464ef209e18e661320100a7b42)
Signed-off-by: Victor Vieux <vieux@docker.com>

contrib/completion/bash/docker

@@ -3223,7 +3223,7 @@ _docker_plugin_create() {
 _docker_plugin_disable() {
 	case "$cur" in
 		-*)
-			COMPREPLY=( $( compgen -W "--help" -- "$cur" ) )
+			COMPREPLY=( $( compgen -W "--force -f --help" -- "$cur" ) )
 			;;
 		*)
 			local counter=$(__docker_pos_first_nonflag)