mathlib

0c57d1e7 - feat(category_theory/monad): algebras for the coproduct monad (#5679)

feat(category_theory/monad): algebras for the coproduct monad (#5679) WIP, I'll fix it up when the dependent PRs merge <!-- put comments you want to keep out of the PR commit here. If this PR depends on other PRs, please list them below this comment, using the following format: - [ ] depends on: #abc [optional extra text] - [ ] depends on: #xyz [optional extra text] --> - [x] depends on: #5674 - [x] depends on: #5677 - [x] depends on: #5678