feat(group_theory/order_of_element): Raising to a coprime power is a bijection (#7923)
feat(group_theory/order_of_element): Raising to a coprime power is a bijection (#7923)

If `gcd(|G|,k)=1` then the `k`th power map is a bijection



Co-authored-by: tb65536 <25c750517795e47f172dc8c552ed72c7de260bd4@users.noreply.github.com>

leanprover-community/mathlib,leanprover-community/mathlib