Re-add VoiceChannel#members and messageUpdate to the documentation

src/client/websocket/packets/handlers/MessageUpdate.js

@@ -11,3 +11,10 @@ class MessageUpdateHandler extends AbstractHandler {
 }
 
 module.exports = MessageUpdateHandler;
+
+/**
+ * Emitted whenever a message is updated - e.g. embed or content change.
+ * @event Client#messageUpdate
+ * @param {Message} oldMessage The message before the update
+ * @param {Message} newMessage The message after the update
+ */