We need docs of Lua API for spells

[NappingOcean]

Is your feature request related to a problem? Please describe.

I'd like to make a mod with using spells by LUA like this, but it's too hard to learn it with the PR only.
Maybe others like me want to know new LUA stuff.

Describe the solution you'd like

The document should be updated with spell contents. Idk details of how it is generated by, but I suppose that some processes would fail partially for it.

Additional context

No response