Add strings.

en.json

@@ -81,6 +81,8 @@
                 "system": {
                     "user_joined": "joined.",
                     "user_left": "left.",
+                    "user_kicked": "was kicked.",
+                    "user_banned": "was banned.",
                     "added_by": "added by",
                     "removed_by": "removed by",
                     "channel_renamed": "renamed the channel to",