Flat records for limits/colimits

[TOTBWF]

Description

This PR flattens out Binary-products et. al into flat records to get better printing.

Currently, this is a draft to get API feedback!

Checklist

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

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

If your change affects many files without adding substantial content, and you don't want your name to appear on those pages (for example, treewide refactorings or reformattings), start the commit message and PR title with chore:.

[Lavenza]

Pull request preview

[ncfavier]

Could we have a test/reproducer for the printing issues with, say, binary products?

[TOTBWF]

I think @plt-amy had a good real world example in https://gist.github.com/plt-amy/9f1efaaef2fe15baf4965be21e60994b, we could use the code that generated the nightmare for that

[ncfavier]

I guess things like δ-natural can serve as test cases. Without this PR the goal is

is-product.⟨ Product.has-is-product (all-products y y) , id ⟩
      id
      ∘ f
      ≡
      is-product.⟨ Product.has-is-product (all-products y y) ,
      f ∘ Product.π₁ (all-products x x) ⟩
      (f ∘ Product.π₂ (all-products x x))
      ∘ is-product.⟨ Product.has-is-product (all-products x x) , id ⟩ id

With this PR it becomes ⟨ id , id ⟩ ∘ f ≡ ⟨ f ∘ π₁ , f ∘ π₂ ⟩ ∘ ⟨ id , id ⟩. Much better!