在website中补充demo示例

Signed-off-by: Nli-yan339 <liyan339@h-partners.com>

zh-cn/device-dev/website.md

@@ -538,6 +538,11 @@
   - [Docker编译环境](get-code/gettools-acquire.md)
   - [IDE集成开发环境](get-code/gettools-ide.md)
 
+- 示例教程
+
+  - [Demo示例](device-demo.md)
+  - [Codelabs](https://gitee.com/openharmony/codelabs/blob/master/README.md) 
+
 - 参考
   - [常见问题概述](faqs/faqs-overview.md)
   - [环境搭建常见问题](faqs/faqs-environment-setup.md)