update docs

Signed-off-by: NAnnie_wang <annie.wangli@huawei.com>

en/application-dev/faqs/faqs-file-management.md

@@ -71,11 +71,14 @@ The **ohos.permission.READ_MEDIA** is required for using **getAlbums()**. In add
 2. Add the code for user authorization before the **MainAbility.ts -> onWindowStageCreate** page is loaded.
   
    ```
+   import abilityAccessCtrl from '@ohos.abilityAccessCtrl.d.ts';
+   
    private requestPermissions() {
    let permissionList: Array<string> = [
      "ohos.permission.READ_MEDIA"
    ];
-   this.context.requestPermissionsFromUser(permissionList)
+   let atManager = abilityAccessCtrl.createAtManager();
+   atManager.requestPermissionsFromUser(this.context, permissionList)
      .then(data => {
        console.info(`request permission data result = ${data.authResults}`)
      })