Add zsh completion for 'docker {create,run} --stop-timeout'

Signed-off-by: Steve Durrheimer <s.durrheimer@gmail.com>

contrib/completion/zsh/_docker

@@ -1481,6 +1481,7 @@ __docker_subcommand() {
         "($help)--privileged[Give extended privileges to this container]"
         "($help)--read-only[Mount the container's root filesystem as read only]"
         "($help)*--security-opt=[Security options]:security option: "
+        "($help)--stop-timeout=[Timeout (in seconds) to stop a container]:time: "
         "($help)*--sysctl=-[sysctl options]:sysctl: "
         "($help -t --tty)"{-t,--tty}"[Allocate a pseudo-tty]"
         "($help -u --user)"{-u=,--user=}"[Username or UID]:user:_users"