refactor:优化gii的crud模块，controller的代码格式

vendor/iron/generators/crud/default/controller.php

@@ -39,6 +39,7 @@ use yii\data\ActiveDataProvider;
 use <?= ltrim($generator->baseControllerClass, '\\') ?>;
 use yii\web\NotFoundHttpException;
 use yii\filters\VerbFilter;
+use iron\widget\Excel;
 
 /**
  * <?= $controllerClass ?> implements the CRUD actions for <?= $modelClass ?> model.
@@ -190,7 +191,7 @@ if (count($pks) === 1) {
         } else {
             $dataProvider = $searchModel->search($params);
         }
-    \iron\widget\Excel::export([
+        Excel::export([
             'models' => $dataProvider->getModels(),
             'format' => 'Xlsx',
             'asAttachment' => true,