Update structure-assets.md

docs/guide/structure-assets.md

@@ -22,7 +22,7 @@ JavaScript files in the bundle in the rendered Web page.
 
 Asset bundles are specified as PHP classes extending from [[yii\web\AssetBundle]]. The name of a bundle is simply
 its corresponding fully qualified PHP class name (without the leading backslash). An asset bundle class should
-should be [autoloadable](concept-autoloading.md). It usually specifies where the assets are located, what CSS and 
+be [autoloadable](concept-autoloading.md). It usually specifies where the assets are located, what CSS and 
 JavaScript files the bundle contains, and how the bundle depends on other bundles.
 
 The following code defines the main asset bundle used by [the basic application template](start-installation.md):