[9.x] Update outdated PHPUnit link and add simple documentation about phpunit.dusk.xml (laravel#8268)

* Use operating system instead of operation system

* Add XML Configration file docs

* Clean up

* Update dusk.md

Co-authored-by: Taylor Otwell <[email protected]>

Author: hpacleb

dusk.md

@@ -65,7 +65,7 @@ composer require --dev laravel/dusk
 > **Warning**
 > If you are manually registering Dusk's service provider, you should **never** register it in your production environment, as doing so could lead to arbitrary users being able to authenticate with your application.
 
-After installing the Dusk package, execute the `dusk:install` Artisan command. The `dusk:install` command will create a `tests/Browser` directory, an example Dusk test, and install the Chrome Driver binary for your operation system:
+After installing the Dusk package, execute the `dusk:install` Artisan command. The `dusk:install` command will create a `tests/Browser` directory, an example Dusk test, and install the Chrome Driver binary for your operating system:
 
 ```shell
 php artisan dusk:install
@@ -179,7 +179,7 @@ If you had test failures the last time you ran the `dusk` command, you may save
 php artisan dusk:fails
 ```
 
-The `dusk` command accepts any argument that is normally accepted by the PHPUnit test runner, such as allowing you to only run the tests for a given [group](https://phpunit.de/manual/current/en/appendixes.annotations.html#appendixes.annotations.group):
+The `dusk` command accepts any argument that is normally accepted by the PHPUnit test runner, such as allowing you to only run the tests for a given [group](https://phpunit.readthedocs.io/en/9.5/annotations.html#group):
 
 ```shell
 php artisan dusk --group=foo