code: @Override
      public Content getModuleHeader(String heading) {
          HtmlTree bodyTree = getBody(true, getWindowTitle(mdle.getQualifiedName().toString()));
          HtmlTree htmlTree = (configuration.allowTag(HtmlTag.HEADER))
                  ? HtmlTree.HEADER()
                  : bodyTree;
          addTop(htmlTree);
          addNavLinks(true, htmlTree);
          if (configuration.allowTag(HtmlTag.HEADER)) {
              bodyTree.addContent(htmlTree);
          }
          HtmlTree div = new HtmlTree(HtmlTag.DIV);
          div.addStyle(HtmlStyle.header);
          Content annotationContent = new HtmlTree(HtmlTag.P);
          addAnnotationInfo(mdle, annotationContent);
          div.addContent(annotationContent);
          Content label = mdle.isOpen() && (configuration.docEnv.getModuleMode() == ModuleMode.ALL)
                  ? contents.openModuleLabel : contents.moduleLabel;
          Content tHeading = HtmlTree.HEADING(HtmlConstants.TITLE_HEADING, true,
                  HtmlStyle.title, label);
          tHeading.addContent(Contents.SPACE);
          Content moduleHead = new RawHtml(heading);
          tHeading.addContent(moduleHead);
          div.addContent(tHeading);
          if (configuration.allowTag(HtmlTag.MAIN)) {
              mainTree.addContent(div);
          } else {
              bodyTree.addContent(div);
          }
          return bodyTree;
      }
docs: Get the module header.
  
  @param heading the heading for the section