!5916 issuse修改

Merge pull request !5916 from 孙悦/OpenHarmony-3.1-Release

zh-cn/application-dev/reference/apis/js-apis-system-time.md

@@ -191,7 +191,7 @@ getRealActiveTime(isNano?: boolean): Promise<number>
 **示例：**
   
   ```js
-  systemTime.getCurrentTime().then((data) => {
+  systemTime.getRealActiveTime().then((data) => {
       console.log(`systemTime.getRealActiveTime success data : ` + JSON.stringify(data));
   }).catch((error) => {
       console.error(`failed to systemTime.getRealActiveTime because ` + JSON.stringify(error));