docker-compose: add alias for `docker-compose kill` (#8997)

plugins/docker-compose/README.md

@@ -28,3 +28,4 @@ plugins=(... docker-compose)
 | dclf      | `docker-compose logs -f` | Show logs and follow output                                      |
 | dcpull    | `docker-compose pull`    | Pull image of a service                                          |
 | dcstart   | `docker-compose start`   | Start a container                                                |
+| dck       | `docker-compose kill`    | Kills containers                                                 |

plugins/docker-compose/docker-compose.plugin.zsh

@@ -24,3 +24,4 @@ alias dcl='docker-compose logs'
 alias dclf='docker-compose logs -f'
 alias dcpull='docker-compose pull'
 alias dcstart='docker-compose start'
+alias dck='docker-compose kill'