Drupal 8: Add view mode suggestion for taxonomy terms.

/**

 * Implements hook_theme_suggestions_alter().

 */

function THEME_theme_suggestions_alter(&$suggestions, $variables, $hook) {

  switch ($hook) {

    case 'taxonomy_term':

      // Add a view mode suggestion for taxonomy terms.

      $suggestions[] = $hook . '__' . $variables['elements']['#view_mode'];

    break;

  }

}