mathlib

43a2b24d - feat(tactic/abel) teach abel to gsmul_zero (#3173)

feat(tactic/abel) teach abel to gsmul_zero (#3173) As reported by Heather Macbeth in: https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/limitations.20of.20.60abel.60 `abel` was not negating zero to zero.