Better generated documentation

[Niols]

This PR:

• cleans up ever so slightly the haddock invocation
• asks Haddock to generate the “Quick Jump” index
• uploads the documentation as artefact so we can download it (eg. to check it manually)

[Niols]

And... it doesn't quite work. That is it works, and you can go try locally by downloading the artifact: https://github.com/tweag/cooked-validators/actions/runs/4252873406. However, the quick jump doesn't work.

This is what I experimented in 35abe52 and this experiment showed that, without the cache, the quick jump index was correctly generated. I think things should be fine if we managed to invalidate the cache and rebuild it in this PR. Alternatively, we can merge this PR and wait for the cache to be reconstructed some time in the future. Then, suddenly, the quick jump feature should start working, as if by...

[Niols]

If one wants to convince oneself that ignoring the cache indeed fixed the quick jump thing, one can follow the checks on commit https://github.com/tweag/cooked-validators/commit/35abe52436f837bffba8cbad65e5b49f8d2a8f0f and end up here: https://github.com/tweag/cooked-validators/actions/runs/4252033415 From there, one can download the documentation, unzip it, serve it locally (eg. with python -m http.server, going via file:// will not work) and play around with it.

[Niols]

Removing comments to invalidate the cache. Noice.

[Niols]

Surprisingly, this doesn't work either. But I think this might have to do with the fallback key of the cache!

[Niols]

Just to check, let me run the experiment again. Same code, same CI, but no cache.