update docs

Signed-off-by: Nzengyawen <zengyawen1@huawei.com>

zh-cn/application-dev/background-agent-scheduled-reminder/Readme-CN.md

-# 后台代理提醒
-
-- [后台代理提醒概述](background-agent-scheduled-reminder-overview.md)
-- [后台代理提醒开发指导](background-agent-scheduled-reminder-guide.md)

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

@@ -3,4 +3,7 @@
 - [公共事件与通知概述](notification-brief.md)
 - [公共事件开发指导](common-event.md)
 - [通知开发指导](notification-guidelines.md)
+- 后台提醒
+  - [后台提醒开发概述](background-agent-scheduled-reminder-overview.md)
+  - [后台提醒开发指导](background-agent-scheduled-reminder-guide.md)
 - [调试助手使用指导](assistant-guidelines.md)
\ No newline at end of file

zh-cn/application-dev/task-management/Readme-CN.md

 # 任务管理
 
-后台任务
-
+- 后台任务
   - [后台任务概述](background-task-overview.md)
   - [后台任务开发指导](background-task-dev-guide.md)
 
-延迟任务调度
-
+- 延迟任务调度
   - [延迟任务调度概述](work-scheduler-overview.md)
   - [延迟任务调度开发指导](work-scheduler-dev-guide.md)
\ No newline at end of file