[generate:command] Regression with the Annotation stops custom translations from working

[codebymikey]

The #4074 PR introduced a regression with the annotations.

The DrupalCommand annotation was missing the @ annotation token prefix, which stops translations from being detected for generated commands as it fails validation and marked as an invalid command in the following: https://github.com/hechoendrupal/drupal-console/blob/e582d885aadcf57694043dc8b02acd151f8fdf98/src/Application.php#L123-L129