feat: extends support

[Tahul]

This PR improves #496 to support @nuxt/content sources.
It adds that support by pushing .nuxt/cache/content/parsed/**/*.md as a Tailwind content source.
Using .nuxt/cache instead of targeting content/ directory has multiple benefits:

• We can ensure the Tailwind HMR happens after the content files has been parsed by @nuxt/content
  • This might lower the chances of encountering V8 errors by stacking FS calls on same HMR updates...
• It supports content coming from multiple sources as they are fetched locally, meaning you can also use Tailwind classes > remote sources

This part has been moved into nuxt/content#1351

The PR also adds a return check on the tailwindcss:config hook, allowing to overwrite the whole Tailwind config from the hook by returning it.
Maybe we could close #498 in the same PR.

The PR now resolves #498 and #488 by providing support for extends layers in the configPath resolving.

It should also resolve #500, that has been introduced by 5.2.0.

configPath key now supports:

• configPath: 'my-config/tailwind.config'
• configPath: ['my-configs/tailwind.config', ...]

These ultimately gets resolved and merged layer-by-layer using defu.

This PR updates the structure of the module.ts file to allow such resolving, so should be reviewed with care.

I checked it myself and can't see any breaking changes, but I would appreciate anyone with some time to review it.

Maybe we could consider making an edge release for this branch @atinux ?

[atinux]

Agree for an edge release to beta test this!

[pi0]

I do not think extending external tailwind config files is the best option. Having the file alone is an anti-pattern for Nuxt projects but with multi-layers, it is probably even not safe as tailwind itself does not do that. (you can still go with it. just sharing my feedback)

Extending support is also a good idea but please note that the current implementation is using undocumented _layers API and it might receive changes. I will try to communicate about this if it happens.

[Tahul]

@atinux ; published @nuxtjs/[email protected]

[atinux]

I believe this one is still an improvement in term of DX for theme author since a tailwind.config is needed for Intelissense to work.

[bmulholland]

This did not resolve #500, which is still an open issue on 5.3.0