code: protected void addOverviewComment(Content htmltree) {
          if (!utils.getFullBody(configuration.overviewElement).isEmpty()) {
              addInlineComment(configuration.overviewElement, htmltree);
          }
      }
docs: Adds the overview comment as provided in the file specified by the
  "-overview" option on the command line.
  
  @param htmltree the documentation tree to which the overview comment will
  be added