Formatting guidelines visual styles removed from filter module

Formatting guidelines markup now only contains necessary classes and attributes to attach JavaScript. All visual classes (filter-wrapper, filter-guidelines, filter-list and filter-help has been removed, as well as all of the CSS (filter.admin.css).

Note: This doesn't affect themes extending Stable or Classy.

These classes can be added back with the following code in your theme:

/**
 * Implements hook_element_info_alter().
 */
function hook_element_info_alter(array &$info) {
  if (array_key_exists('text_format', $info)) {
    $info['text_format']['#process'][] = 'themename_process_text_format';
  }
}

/**
 * #process callback, for adding classes to filter components.
 *
 * @param array $element
 *   Render array for the text_format element.
 *
 * @return array
 *   Text_format element with the filter classes added.
 */
function themename_process_text_format(array $element) {
  $element['format']['#attributes']['class'][] = 'filter-wrapper';
  $element['format']['guidelines']['#attributes']['class'][] = 'filter-guidelines';
  $element['format']['format']['#attributes']['class'][] = 'filter-list';
  $element['format']['help']['#attributes']['class'][] = 'filter-help';

  return $element;
}