mathlib

632783df - feat(algebra/subalgebra): two equal subalgebras are equivalent (#7590)

feat(algebra/subalgebra): two equal subalgebras are equivalent (#7590) This extends `linear_equiv.of_eq` to an `alg_equiv` between two `subalgebra`s. [Zulip discussion starts around here](https://leanprover.zulipchat.com/#narrow/stream/113489-new-members/topic/towers.20of.20algebras/near/238452076) Co-authored-by: Anne Baanen <Vierkantor@users.noreply.github.com>