Add concrete domain name directory to example code

[maru0914]

Added concrete domain name directory for consistency with other places.

Other Places

1. Subsequent example on the same page
   

   docs/events.md

   Lines 93 to 94 in 33d43e1

   	use App\Domain\Orders\Events\PodcastProcessed;
   	use App\Domain\Orders\Listeners\SendPodcastNotification;

2. artisan.md example
   

   docs/artisan.md

   Lines 660 to 662 in 33d43e1

   	->withCommands([
   	__DIR__.'/../app/Domain/Orders/Commands',
   	])