feat(data/nat/gcd): `coprime.lcm_eq_mul` (#9761)
feat(data/nat/gcd): `coprime.lcm_eq_mul` (#9761)

Surprisingly, this result doesn't seem to be present yet.



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

leanprover-community/mathlib,leanprover-community/mathlib