chore(data/equiv/fin): simp definitional lemmas (#5740)
chore(data/equiv/fin): simp definitional lemmas (#5740)

Co-authored-by: Eric Wieser <da64e90baec5d084ce3d8e05f3b022ae6d118ff5@gmail.com>





leanprover-community/mathlib,leanprover-community/mathlib