docs: add the flasher:install command need after composer require step

docs/pages/library/sweetalert.md

@@ -13,6 +13,9 @@ data-controller: sweetalert
 ```shell
 composer require php-flasher/flasher-sweetalert-laravel
 ```
+```shell
+php artisan flasher:install
+```
 
 <br />
 
@@ -21,6 +24,9 @@ composer require php-flasher/flasher-sweetalert-laravel
 ```shell
 composer require php-flasher/flasher-sweetalert-symfony
 ```
+```shell
+php bin/console flasher:install
+```
 
 ---