docs: correct help output

Refs dokku/dokku-postgres#197

help-functions

@@ -164,8 +164,8 @@ fn-help-list-example() {
   # shellcheck disable=SC2034
   declare desc="return $PLUGIN_COMMAND_PREFIX plugin help content"
   cat <<help_list
-      NAME, VERSION, STATUS, EXPOSED PORTS, LINKS
+      $PLUGIN_SERVICE services
-      service-name, $PLUGIN_COMMAND_PREFIX:$PLUGIN_IMAGE_VERSION, running, -, app-name
+      service-name
 help_list
 }