add missing docs

src/events/payload.rs

@@ -285,5 +285,8 @@ pub enum EventType {
 
     /// Inform UI that a single chat list item changed and needs to be rerendered
     /// If `chat_id` is set to None, then all currently visible chats need to be rerendered, and all not-visible items need to be cleared from cache if the UI has a cache.
-    UIChatListItemChanged { chat_id: Option<ChatId> },
+    UIChatListItemChanged { 
+        /// ID of the changed chat
+        chat_id: Option<ChatId>
+    },
 }