code: String convertCase(String s, String sample, Language lang) {
      return CaseConversionHelper.convertCase(match.getCaseConversionType(), s, sample, lang);
    }
docs: Converts case of the string token according to match element attributes.
  @param s Token to be converted.
  @param sample the sample string used to determine how the original string looks like (used only on case preservation)
  @return Converted string.