!3346 格式修改+add sample

Merge pull request !3346 from zengyawen/master

zh-cn/application-dev/connectivity/ipc-rpc-overview.md

 # IPC与RPC通信概述
 
-- [基本概念](#基本概念)
-- [约束与限制](#约束与限制)
-- [相关模块](#相关模块)
 
 ## 基本概念
 

zh-cn/application-dev/notification/notification.md

@@ -263,3 +263,5 @@ Notification.cancel(1, "label", cancelCallback)
 针对通知开发，有以下相关可供参考：
 
 - [`Notification`：通知-订阅、发送通知（eTS）（API9）](https://gitee.com/openharmony/app_samples/tree/master/Notification/Notification)
+
+- [`Notification`：通知（eTS）（API7）](https://gitee.com/openharmony/app_samples/tree/master/common/Notification)