docs: private static String getOperatorId(AstNode operatorFunctionId) {
  
      StringBuilder builder = new StringBuilder(
        operatorFunctionId.getTokenValue());
      AstNode operator = operatorFunctionId
        .getFirstDescendant(CxxGrammarImpl.overloadableOperator);
  
      if (operator != null) {
  
        AstNode opNode = operator.getFirstChild();
        while (opNode != null) {
          builder.append(opNode.getTokenValue());
          opNode = opNode.getNextSibling();
        }
      }
  
      return builder.toString();
    }