!2472 async bug

Merge pull request !2472 from fanchenxuan/master

zh-cn/application-dev/security/accesstoken-guidelines.md

@@ -24,6 +24,7 @@
   import abilityAccessCtrl from '@ohos.abilityAccessCtrl'
   import bundle from '@ohos.bundle'
 
+  async requestPermission() {
     var permissionNameUser = "ohos.permission.ALPHA";
     var bundleFlag = 0;
     var tokenID = undefined;
@@ -39,6 +40,7 @@
     } else {
         // 申请动态授权，使用接口：requestPermissionsFromUser
     }
+  }
 
 ```
 > **说明：**