update docs

Signed-off-by: Nzengyawen <zengyawen1@huawei.com>

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

@@ -26,7 +26,7 @@ createAppAccountManager(): AppAccountManager
 
 **示例：**
   ```js
-  var appAccountManager = account_appAccount.createAppAccountManager();
+  const appAccountManager = account_appAccount.createAppAccountManager();
   ```
 
 ## AppAccountManager

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

@@ -117,7 +117,7 @@ createAudioRecorder(): AudioRecorder
 **示例：**
 
 ```js
-let audiorecorder = media.createAudioRecorder();
+let audioRecorder = media.createAudioRecorder();
 ```
 
 ## media.createVideoRecorder<sup>9+</sup>