update themer utility

docs/utilities/themer.md

@@ -8,18 +8,16 @@ Themer is a utility that allows users to switch between light and dark themes. I
 
 ## Usage
 
-By default, themer is included in the `resources/layouts/scaffold.blade.php` file. You can include it in your layout file by adding the following line:
+You can include themer in your layout file by adding the following line:
 
 ```blade
-<script src="{{ hashed_asset('assets/js/themer.js') }}"></script>
+@themer()
 ```
 
-By default, themer script will look for the `themerKey` key in the window object to store the theme in local storage. You can change the key by setting the `themerKey` variable before including the script.
+By default, themer script will look for the `themerKey` key in the window object to store the theme in local storage. You can change the key by passing the `themerKey` to the `@themer` directive.
 
 ```blade
-<script>
-    window.themerKey = 'new-key';
-</script>
+@themer('key')
 ```
 
 Currently, dashboard layout uses the `dashboard-theme` key to store the theme in local storage, while the website layout uses the `website-theme` key.