Add a contributing guide

[EdricChan03]

A contributing guide for this repository would be ideal for first-time contributors (e.g. how to set up the project for local development, adding new features, navigating around the codebase, commit guidelines, etc), and also standardises project conventions/rules (if any) for existing contributors.

[aSemy]

I totally agree that more documentation is necessary, so if you want to see something specific feel free to propose it. While I could write loads of docs, I suspect that I'd write a lot of words that no one would read :)

I'm a bit concerned that any documentation would just become out of date (unless it was tested using Knit or something, but that's also additional work/overhead).

Also, keep in mind that this project has a tenuous future. The aim is to merge into the main Dokka repo, so it's a good idea to try and keep the projects aligned, and also be aware that any work might be removed during this potential merge.

how to set up the project for local development

Just checking it out and running ./gradlew build or ./gradlew check should work fine

adding new features

It's usually better to make an issue first, rather than a PR. This would help getting the purpose clear, or to prevent double work. However, I think sometimes a PR-first approach can be helpful to demonstrate the end result.

navigating around the codebase

What sort of docs would help with navigating? Is there something in particular you had in mind?

commit guidelines

I've enabled squash commits on the PRs, and that's all I really care about.