Fixes #2572: Corrected LanguageAsset example

docs/guide/assets.md

@@ -81,18 +81,26 @@ following way:
 ```php
 class LanguageAsset extends AssetBundle
 {
-    public $sourcePath = '@app/assets/language';
-    public $js = [
-    ];
-
-    public function init()
-    {
-        $this->js[] = 'language-' . Yii::$app->language . '.js';
-        parent::init();
-    }
+	public $language;
+	public $sourcePath = '@app/assets/language';
+	public $js = [
+	];
+
+	public function registerAssetFiles($view)
+	{
+		$language = $this->language ? $this->language : Yii::$app->language;
+		$this->js[] = 'language-' . $language . '.js';
+		parent::init();
+	}
 }
 ```
 
+In order to set language use the following code when registering an asset bundle in a view:
+
+```php
+LanguageAsset::register($this)->language = $language;
+```
+
 
 Registering asset bundle
 ------------------------