Complete running containers correctly after docker rm -vf in Zsh

When using option-stacking the -f flag that controls completing running
containers can be a part of another word of options, so use opt_args
that contains the parsed arguments from _arguments to check for it
instead.

Signed-off-by: Segev Finer <segev208@gmail.com>

contrib/completion/zsh/_docker

@@ -838,7 +838,7 @@ __docker_container_subcommand() {
                 "($help -)*:containers:->values" && ret=0
             case $state in
                 (values)
-                    if [[ ${words[(r)-f]} == -f || ${words[(r)--force]} == --force ]]; then
+                    if [[ -n ${opt_args[(i)-f]} || -n ${opt_args[(i)--force]} ]]; then
                         __docker_complete_containers && ret=0
                     else
                         __docker_complete_stopped_containers && ret=0