mathlib

5305d39a - feat(data/pnat/basic): `succ` as an order isomorphism between `ℕ` and `ℕ+` (#15183)

feat(data/pnat/basic): `succ` as an order isomorphism between `ℕ` and `ℕ+` (#15183) Couldn't find this in the library. Asked on [Zulip](https://leanprover.zulipchat.com/#narrow/stream/217875-Is-there-code-for-X.3F/topic/order.20isomorphism.20between.20.E2.84.95.20and.20.E2.84.95.2B/near/288891689) in case anyone knew of this already.