Issue #3317370 by weseze: Remove (undefined) dependency on the help module

use Drupal\Core\Url;

use Drupal\Core\Form\ConfigFormBase;

use Drupal\Core\Form\FormStateInterface;

use Drupal\Core\Extension\ModuleHandlerInterface;

use Symfony\Component\DependencyInjection\ContainerInterface;

/**

 */

class ConfigTokensForm extends ConfigFormBase {

  /**

   * Module Handler service object.

   *

   * @var \Drupal\Core\Extension\ModuleHandlerInterface

   */

  protected $moduleHandler;

  /**

   * Constructor for Config Tokens.

   *

   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler

   *   Module Handler service object.

   */

  public function __construct(ModuleHandlerInterface $module_handler) {

    $this->moduleHandler = $module_handler;

  }

  /**

   * {@inheritdoc}

   */

  public static function create(ContainerInterface $container) {

    return new static(

      $container->get('module_handler'),

    );

  }

  /**

   * {@inheritdoc}

   */

      }

    }

    if ($this->moduleHandler->moduleExists('help')) {

      $markup = '<p>' . t('See the list of <a href=":field#token-config-token" target="_blank">available tokens</a>. For more information, see the <a href=":docs" target="_blank">online documentation.</a></p>',

        [

          ':field' => Url::fromRoute('help.page', ['name' => 'token'])->toString(),

          ':docs' => Url::fromRoute('help.page', ['name' => 'config_token'])->toString()

      ]);

        ]

      );

      $form['values'][]['help'] = array(

        '#markup' => $markup,

          'colspan' => 2,

        ),

      );

    }

    return parent::buildForm($form, $form_state);

  }