Update help to support developers

[tapika]

Would it be possible to write down better documentation - what are steps to take this into use.
What tools you need to install (e.g. pandoc), etc...

[LiarOnce]

I will improve this document, but these scripts are only prepared for GameMaker Manual. I don't know whether they are applicable to other documents made with RoboHelp.

[tapika]

I have tried on my own help project, it does works but html output is bit messed. That why missed doc on what and how was done.

[LiarOnce]

If you need to make targeted adaptation for other projects, make modifications here to adapt your project:
https://github.com/GamemakerChina/robohelp-to-markdown-script/blob/main/main.py#L39