code: protected Pattern p(String regex) {
          return p(regex, Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
      }
docs: Creates a case insensitive regex pattern. This method is used by
  {@code irregular, plural} and {@code singular}.
  @param regex
  @return pattern
  @see RegexPluralizer#irregular(java.lang.String, java.lang.String)
  @see RegexPluralizer#plural(java.lang.String, java.lang.String)
  @see RegexPluralizer#singular(java.lang.String, java.lang.String)