do attack speed slows proc stoneborn?

any form of cc i believe

but attack speed slows shouldnt... but im not sure

Your crowd control effects brand enemy champions with an Earthen Rune for 4 seconds. Other allied champions who attack branded enemies heal for 5 (+ 2.5% of your maximum health) over 2 seconds (halved to 2.5 (+ 1.25% of your maximum health) if you are ranged).

They lumped in attack speed slows alongside slows a while back, so it should.