feat(algebra/group_with_zero): add units.can_lift (#7857)
feat(algebra/group_with_zero): add units.can_lift (#7857)

[Zulip](https://leanprover.zulipchat.com/#narrow/stream/116395-maths/topic/projective.20space/near/242041169)





leanprover-community/mathlib,leanprover-community/mathlib