docs: function styleStrike(sq) {
    if (sq.hasFormat('S')) {
      sq.changeFormat(null, {tag: 'S'});
    } else if (!sq.hasFormat('a') && !sq.hasFormat('PRE')) {
      if (sq.hasFormat('code')) {
        sq.changeFormat(null, {tag: 'code'});
      }
      sq.strikethrough();
    }
  }