code: public Content getMarkerAnchor(String anchorName, Content anchorContent) {
          if (anchorContent == null)
              anchorContent = new Comment(" ");
          Content markerAnchor = HtmlTree.A(configuration.htmlVersion, anchorName, anchorContent);
          return markerAnchor;
      }
docs: Get the marker anchor which will be added to the documentation tree.
  
  @param anchorName the anchor name or id attribute
  @param anchorContent the content that should be added to the anchor
  @return a content tree for the marker anchor