src/common/util.js/getParserName
function getParserName(lang, options) {
  const supportInfo = support.getSupportInfo({ plugins: options.plugins });
  const language = supportInfo.languages.find(
    (language) =>
      language.name.toLowerCase() === lang ||
      (language.aliases && language.aliases.includes(lang)) ||
      (language.extensions &&
        language.extensions.find((ext) => ext === `.${lang}`))
  );
  if (language) {
    return language.parsers[0];
  }

  return null;
}