code: public void onComment (@Nullable final String sComment)
    {
      if (StringHelper.hasText (sComment))
      {
        if (isThrowExceptionOnNestedComments ())
          if (sComment.contains (COMMENT_START) || sComment.contains (COMMENT_END))
            throw new IllegalArgumentException ("XML comment contains nested XML comment: " + sComment);
  
        _append (COMMENT_START)._append (sComment)._append (COMMENT_END);
      }
    }
docs: Comment node.
  
  @param sComment
  The comment text