Documentation generation

[TheJJ]

We could add some means of documentation format (like the python docstrings).
That would allow generation of API pages, so mod developers can use this as reference instead of looking at the nyan files.

[simonsan]

Don't know if it's the right issue to add this:

1. Idea: Sphinx
   Developing extensions for Sphinx
   We could develop a small extension for sphinx (done in python) that lets us or everyone else create documentation directly from nyan-files.
   Examples for developing an extension can be found here.

2. Role model: Rustdoc
   I also love the rustdoc approach. What is rustdoc? As I would propose it, it would be some kind of a tool, let's call it nyandoc for now, that you can give a path to a modpack/nyan-file and it automatically documents everything and creates a tiny html-page out of it that you can package/use as a website/or let people generate themselves at home. (this example is more openage specific though)

Approach 1 is probably easier and faster to accomplish, but has sphinx and python as a dependency, approach 2 would give us more freedom but seems more like a long-term approach.