Update src/guide/intro/upgrade-from-v2.md

Co-authored-by: Copilot <[email protected]>

Author: samdark

src/guide/intro/upgrade-from-v2.md

@@ -89,7 +89,7 @@ but might be alien to users of Yii 1.1 and Yii 2.0.
 
 ### Handlers
 
-Unlike Yii 2.0, Yii3 doesn't have controllers concept. Instead, it uses [handlers](../structure/handler.md) which
+Unlike Yii 2.0, Yii3 doesn't use controllers. Instead, it uses [handlers](../structure/handler.md) which
 are similar to controllers but different.
 
 ### Application structure