function titleize(str, opts) {
  if (opts && opts.strip) { return strip(str, opts); }
  if (opts && opts.titleize === false) return str;
  if (opts && typeof opts.titleize === 'function') {
    return opts.titleize(str, opts);
  }
  str = utils.getTitle(str);
  str = str.split(/<\/?[^>]+>/).join('');
  str = str.split(/[ \t]+/).join(' ');
  return str.trim();
}
Titleize the title part of a markdown link.

@name  options.titleize
@param  {String} `str` The string to titleize
@param  {Object} `opts` Pass a custom titleize function on `titleize`
@return {String}
@api public