We might be able to do it though. Have a snippet to run xml or plain text file with the corresponding documentation address page. SO everytime the snippet is run, it will browse the page step-by-step following the given xml or text file that we can call it table-of-content. This way, when we have a new addition, all we need is to run this snippet, and get the corresponding pdf file.
DOes it sounds complicated? I think so

This can be put as a side project, when the documentation team have time to devellope this kind of tool, so that the doc can be included with modx distribution as well.
Sincerely,