docs: function selectLanguage(options, lang) {
      let langToUse = lang;
      if (langToUse === '' && options.defaultLanguageForUnspecified !== undefined) {
          langToUse = options.defaultLanguageForUnspecified;
      }
      let prismLang = loadPrismLang(langToUse);
      if (prismLang === undefined && options.defaultLanguageForUnknown !== undefined) {
          langToUse = options.defaultLanguageForUnknown;
          prismLang = loadPrismLang(langToUse);
      }
      return [langToUse, prismLang];
  }