Point-set topology

[TOTBWF]

Description

Doing a bit of point-set topology for Borceux/taboos.

Todos

• [ ] Finish writing prose: in particular, the introduction needs to be much better.
• [ ] Finalize the API: right now inference is not great. Organizing things via displayed category theory seems like the right move, but you need to supply a lot of implicits currently.

Checklist

Before submitting a merge request, please check the items below:

• [x] I've read the contributing guidelines.
• [ ] The imports of new modules have been sorted with support/sort-imports.hs (or nix run --experimental-features nix-command -f . sort-imports).
• [ ] All new code blocks have "agda" as their language.

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