mathlib

a478f91b - chore(algebra/ring): move `add_mul_self_eq` to `comm_semiring` (#3089)

chore(algebra/ring): move `add_mul_self_eq` to `comm_semiring` (#3089) Also use `alias` instead of `def ... := @...` to make linter happy. Fixes https://github.com/leanprover-community/lean/issues/232