为更新日历事件添加通知时添加备注。

代码示例：

// 获取日历事件的管理器
CalendarManager calendarManager = context.getSystemService(CalendarManager.class);

// 获取要更新的日历事件
CalendarEvent event = calendarManager.getEvent(eventId);

// 设置通知
Notification notification = new Notification.Builder(context, channelId)
        .setContentTitle(event.getTitle())
        .setContentText(event.getDescription())
        .setSmallIcon(R.drawable.notification_icon)
        .addExtra(Notification.EXTRA_NOTE, "这是一条通知备注")
        .build();
calendarManager.scheduleNotification(notification, event);