Permit exclamation mark ! punctuation at end of parameter comment

It is common practice to use exclamation marks to indicate special conditions on parameters.

This should be permitted without giving the error:

Parameter comment must end with a full stop.

Simple case:

  /**
   * Supplies a basic menu item product.
   *
   * @param string $title
   *   Required !
   * @param string $path
   *   Required !
   *
   * @return \Drupal\ooe\Menu\IMenuItem
   *   A new menu item.
   */
  public function newMenuItem($title, $path);

More complex case:

  /**
   * Add a validation handler to a form.
   *
   * @param array $form
   *   A Drupal form array.
   * @param string $validatorMethodName
   *   The name of a _static_ validator method (only) with signature
   *   ($form, &$form_state); DO NOT include the class name !
   */
  protected function addValidateHandler(array &$form, $validatorMethodName) {