mathlib

e871be25 - feat(data/real/nnreal): floor_semiring instance (#12495)

feat(data/real/nnreal): floor_semiring instance (#12495) [Zulip thread](https://leanprover.zulipchat.com/#narrow/stream/217875-Is-there.20code.20for.20X.3F/topic/.60nat.2Eceil.60.20on.20.60nnreal.60.20.3F/near/274353230)