Trusted callbacks can now be marked with attributes as well as an interface

Previously, trusted callbacks must be implemented with an interface and method declaring the name of the trusted methods:

use Drupal\Core\Security\TrustedCallbackInterface;

class SomeClass implements TrustedCallbackInterface {
  public static function someCallback(...) {
  ...
  }

  /**
   * {@inheritdoc}
   */
  public static function trustedCallbacks() {
    return ['someCallback'];
  }
}

Instead, the interface is no longer required and you can now mark the callback directly with a PHP attribute:

use Drupal\Core\Security\Attribute\TrustedCallback;

class SomeClass {
  #[TrustedCallback]
  public static function someCallback(...) {
  ...
  }
}