fix broken link for icons (#686)

Author: dks333

core-concepts/pages.mdx

@@ -48,7 +48,7 @@ icon: "code"
 ---
 ```
 
-You can set icons from [Font Awesome](https://fontawesome.com/icons) and [Lucide](https://lucide.dev/icons), depending on the [icon library setting](http://localhost:3000/core-concepts/settings#param-icons).
+You can set icons from [Font Awesome](https://fontawesome.com/icons) and [Lucide](https://lucide.dev/icons), depending on the [icon library setting](/core-concepts/settings#param-icons).
 
 You can also set the icon type for Font Awesome icons (optional). If not set, the icon type will be regular.