chore(algebra/group/units): Make coercion the simp-normal form of units (#8568)
chore(algebra/group/units): Make coercion the simp-normal form of units (#8568)

It's already used as the output for `@[simps]`; this makes `↑u` the simp-normal form of `u.val` and `↑(u⁻¹)` the simp-normal form of `u.inv`.





leanprover-community/mathlib,leanprover-community/mathlib