Merge pull request #730 from Ryadnov/fix_typos_in_docs

fix typos - `Yii::app()`

framework/yii/web/Response.php

@@ -515,7 +515,7 @@ class Response extends \yii\base\Response
 	 * **Example**
 	 * 
 	 * ~~~
-	 * Yii::app()->request->xSendFile('/home/user/Pictures/picture1.jpg');
+	 * Yii::$app->request->xSendFile('/home/user/Pictures/picture1.jpg');
 	 * ~~~
 	 *
 	 * @param string $filePath file name with full path

framework/yii/widgets/Menu.php

@@ -37,7 +37,7 @@ use yii\helpers\Html;
  *             array('label' => 'New Arrivals', 'url' => array('product/index', 'tag' => 'new')),
  *             array('label' => 'Most Popular', 'url' => array('product/index', 'tag' => 'popular')),
  *         )),
- *         array('label' => 'Login', 'url' => array('site/login'), 'visible' => Yii::app()->user->isGuest),
+ *         array('label' => 'Login', 'url' => array('site/login'), 'visible' => Yii::$app->user->isGuest),
  *     ),
  * ));
  * ~~~