fix: use getWebSockets method

Author: exectx

src/content/docs/workers/tutorials/live-cursors-with-nextjs-rpc-do/index.mdx

@@ -202,8 +202,9 @@ that will be made available to the Next.js Worker using a [`WorkerEntrypoint`](/
 		}
 
 		broadcast(message: WsMessage, self?: string) {
-			this.sessions.forEach((session, ws) => {
-				session.id !== self && ws.send(JSON.stringify(message));
+			this.ctx.getWebSockets().forEach((ws) => {
+				const { id } = ws.deserializeAttachment();
+				if (id !== self) ws.send(JSON.stringify(message));
 			});
 		}