feat(data/equiv/mul_add): minor lemmas (#3447)
feat(data/equiv/mul_add): minor lemmas (#3447)



Co-authored-by: Chris Hughes <b6f42777c6934d5d432f4754eab7d808cdca21a6@users.noreply.github.com>

leanprover-community/mathlib,leanprover-community/mathlib