Windspeakers applies to lifesteal too?

So I had a game against nasus that used windspeakers blessing and apparently the keystone applies to nasus's passive lifesteal, which I did not know cause I thought it only applied to heals and shields. So not only does windspeakers buff heals and shields, but also lifesteal and spellvamp. I didn't know that so just wanted to ask here to get confirmation.

Btw how I differentiate lifesteal and healing is that lifesteal is a passive ability whereas healing is an active.