code: static String capitalizeAsciiOnly(String s) {
      if (s == null || s.isEmpty()) {
        return s;
      }
      char c = s.charAt(0);
      if (isLowerCaseAsciiOnly(c)) {
        return Character.toUpperCase(c) + s.substring(1);
      }
      return s;
    }
docs: Capitalizes the first character of {@code s}. If {@code s} is {@code null} or empty,
  {@code s} is returned unmodified