update zh-cn/application-dev/ability/stage-serviceextension.md.

Signed-off-by: N@ge-yafang <geyafang@huawei.com>
Signed-off-by: N葛亚芳 <geyafang@huawei.com>

zh-cn/application-dev/ability/stage-serviceextension.md

@@ -75,8 +75,3 @@ ExtensionAbility，是Stage模型中新增的扩展组件的基类，一般用
     "srcEntrance": "./ets/ServiceExtAbility/ServiceExtAbility.ts"    
 }]
 ```
-
-## 相关实例
-
-针对ServiceExtensionAbility开发，有以下相关实例可供参考：
-- [`ServiceExtAbility`：StageExtAbility的创建与使用（eTS）（API9）](https://gitee.com/openharmony/app_samples/tree/master/ability/ServiceExtAbility)