mathlib

89654c0f - feat(data/equiv/{mul_add,ring}): Coercions to types of morphisms from their `_class` (#12243)

feat(data/equiv/{mul_add,ring}): Coercions to types of morphisms from their `_class` (#12243) Add missing coercions to `α ≃+ β`, `α ≃* β`, `α ≃+* β` from `add_equiv_class`, `mul_equiv_class`, `ring_equiv_class`.