mathlib

eb13f6b7 - feat(ring_theory/derivation): add missing dsimp lemmas, use old_structure_command, golf structure proofs (#8013)

feat(ring_theory/derivation): add missing dsimp lemmas, use old_structure_command, golf structure proofs (#8013) This adds a pile of missing coercion lemmas proved by refl, and uses them to construct the `add_comm_monoid`, `add_comm_group`, and `module` instances. This also changes `derivation` to be an old-style structure, which is more in line with the other bundled homomorphisms. This also removes `derivation.commutator` to avoid having two ways to spell the same thing, as this leads to lemmas being harder to apply