New replacements for strings.

en.json

@@ -80,15 +80,15 @@
                     "several": "Several people are typing…"
                 },
                 "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",
-                    "channel_description_changed": "changed the channel description",
-                    "channel_icon_changed": "changed the channel icon"
+                    "user_joined": "{{user}} joined.",
+                    "user_left": "{{user}} left.",
+                    "user_kicked": "{{user}} was kicked.",
+                    "user_banned": "{{user}} was banned.",
+                    "added_by": "{{user}} added by {{other_user}}",
+                    "removed_by": "{{user}} removed by {{other_user}}",
+                    "channel_renamed": "{{user}} renamed the channel to {{other_user}}",
+                    "channel_description_changed": "{{user}} changed the channel description",
+                    "channel_icon_changed": "{{user}} changed the channel icon"
                 },
                 "start": {
                     "group": "This is the start of your conversation."