docs: public static boolean isValidNCName(String ncName) {
      final int length = ncName.length();
      if (length == 0) {
        return false;
      }
      char ch = ncName.charAt(0);
      if (!isNCNameStart(ch)) {
        return false;
      }
      for (int i = 1; i < length; ++i) {
        ch = ncName.charAt(i);
        if (!isNCName(ch)) {
          return false;
        }
      }
      return true;
    }