Get the health healed in onHeal of HealthComp

[lajbel]

Would be cool if we can have the healed health in the onHeal event, such like:

onHeal((heal) => {
    if(heal> 100) k.play("yupi")
})

And will be cool if there's the same option for onHurt.

[slmjkdbtl]

Added in a809620