fixed 8a3185b5 from https://gitee.com/liaokk/docs/pulls/5771

fixed d7d782bc from https://gitee.com/liaokk/docs/pulls/5770
示例代码修改
Signed-off-by: N廖康康 <liaokangkang@huawei.com>

zh-cn/application-dev/reference/apis/js-apis-backgroundTaskManager.md

@@ -127,6 +127,7 @@ cancelSuspendDelay(requestId: number): void
 
 **示例**：
   ```js
+  let id = 1;
   backgroundTaskManager.cancelSuspendDelay(id);
   ```