Refactor `tidy` package dependency usage

### Is there an existing issue outlining your improvement?

- [x] I have searched the existing issues and my improvement has not been raised yet.

### What would you like to see added and/or changed?

Currently, we use [Tidy](https://typst.app/universe/package/tidy/) to generate documentation. I have been thinking about cleaning something up in the `catppuccin` package, which exposes some tooling to make the document theming possible, but it really should be its own package that depends on catppuccin.

`Tidy` isn't well optimised to allow custom styling and, as a result, the current files [tidy/styles.typ](https://github.com/catppuccin/typst/blob/main/src/tidy/styles.typ) and [tidy/show-module.typ](https://github.com/catppuccin/typst/blob/main/src/tidy/show-module.typ) are not overly flexible. Furthermore, I believe `show-module` is a little outdated.

This issue would require completing two tasks:
- [ ] Refactor `show-module.typ` to be up-to-date and allow passthrough of additional arguments.
- [ ] Revisit `styles.typ`. Can this, along with `show-modules.typ`, be improved? At the very least, it should be slightly more flexible. Tidy already isn't flexible, so allowing a bit of modularity prevents users from needing to effectively copy/paste our src to make additions (e.g., doc type colours).

Start by reading src/tidy/show-module.typ and src/tidy/styles.typ, then trace how Tidy and show-modules.typ are used in the documentation setup. Compare show-module.typ with the current Tidy interface and identify the required passthrough and modularity changes. Done means both listed refactoring tasks are addressed without requiring users to copy the package sources.

Written by the indexing model from the issue text.