update zh-cn/application-dev/ability/fa-serviceability.md.

Signed-off-by: Nql <qianli16@huawei.com>

zh-cn/application-dev/ability/fa-serviceability.md

@@ -208,6 +208,7 @@ function onFailedCallback(code){
 
 ```ts
 import deviceManager from '@ohos.distributedHardware.deviceManager';
+var dmClass;
 function getRemoteDeviceId() {
     if (typeof dmClass === 'object' && dmClass != null) {
         var list = dmClass.getTrustedDeviceListSync();
@@ -243,6 +244,8 @@ var connId = featureAbility.connectAbility(
 在跨设备场景下，需要向用户申请数据同步的权限。具体示例代码如下：
 
 ```ts
+import accessControl from "@ohos.abilityAccessCtrl";
+import bundle from '@ohos.bundle';
 async function RequestPermission() {
   console.info('RequestPermission begin');
   let array: Array<string> = ["ohos.permission.DISTRIBUTED_DATASYNC"];