The wrong death message is displayed when being killed by a mob's smash attack.

Steps to reproduce:

1. Build a 4 block-high pillar
2. Summon a husk that can pick up items on top of it:

   /summon husk ~ ~ ~ {CanPickUpLoot:true}

3. Give the husk a mace
4. Go into survival mode
5. Run /damage @s 19
6. Get killed by the husk's smash attack

Observed result:
The death message that is displayed is "<player> was slain by Husk".

Expected result:
The death message that is displayed is "<player> was smashed by Husk".