Slayer trait from Teamfight Tactics Set #4.5

Slayers gain Lifesteal that gets stronger as their own Health decreases, and deal bonus damage that scales up based on their target's missing Health.

(@MinUnits@) @LifestealBase@ to @LifestealMax@% Lifesteal and @BonusDamageBase@ to @BonusDamageMax@% Bonus Damage