code: @RequiresNonNull("docFile")
    private String newDocFileText() throws Exception {
      StringJoiner b = new StringJoiner(lineSep);
      BufferedReader doc = Files.newBufferedReader(docFile.toPath(), UTF_8);
      String docline;
      boolean replacing = false;
      boolean replacedOnce = false;
      String prefix = null;
  
      while ((docline = doc.readLine()) != null) {
        if (replacing) {
          if (docline.trim().equals(endDelim)) {
            replacing = false;
          } else {
            continue;
          }
        }
  
        b.add(docline);
  
        if (!replacedOnce && docline.trim().equals(startDelim)) {
          if (formatJavadoc) {
            int starIndex = docline.indexOf('*');
            b.add(docline.substring(0, starIndex + 1));
            String jdoc = optionsToJavadoc(starIndex, 100);
            b.add(jdoc);
            if (jdoc.endsWith("</ul>")) {
              b.add(docline.substring(0, starIndex + 1));
            }
          } else {
            b.add(optionsToHtml(0));
          }
          replacedOnce = true;
          replacing = true;
        }
      }
  
      doc.close();
      return b.toString();
    }
docs: Get the result of inserting the options documentation into the docfile.
  
  @return the docfile, but with the command-line argument documentation updated
  @throws Exception if there is trouble reading files