mathlib3

18330f63 - feat(tactic/abel): support 0 in group expressions (#11201)

feat(tactic/abel): support 0 in group expressions (#11201) [As reported on Zulip.](https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/.60abel.60.20not.20rewriting.20with.20.60sub_zero.60/near/266645648) fixes #11200