优化errorManager部分示例代码。

Signed-off-by: zyjhandsome <zyjhandsome@126.com>

zh-cn/application-dev/reference/apis/js-apis-inner-application-errorObserver.md

@@ -22,15 +22,14 @@ onUnhandledException(errMsg: string): void;
 import errorManager from '@ohos.app.ability.errorManager';
 
 let observer = {
-    onUnhandledException(errorMsg) {
-        console.log('onUnhandledException, errorMsg: ', errorMsg);
-    }
+  onUnhandledException(errorMsg) {
+    console.log('onUnhandledException, errorMsg: ', errorMsg);
+  }
 };
 
 try {
-    errorManager.on('error', observer);
-} catch (error) {
-    console.log('registerErrorObserver' + ' failed, error.code: ' + JSON.stringify(error.code) +
-        ' error.message: ' + JSON.stringify(error.message));
+  errorManager.on('error', observer);
+} catch (err) {
+  console.log(`registerErrorObserver failed, code is ${err.code}, message is ${err.message}`);
 }
 ```