When you are killed by a potion (like Splash Potion of Harming), your death message reads 'Player was killed by magic'. By renaming items like swords, your death message changes according to the name of said item.

What I expected to happen was:
Renaming a potion of harming and killing a player with it will result in an altered death message.

What happened was:
Death message still reads 'Player was killed by magic'.

Steps to reproduce:

• Go into crative mode, get some Splash Potions of Harming
• Rename them using an anvil
• Go into survival mode
• Kill yourself using the renamed potions

Might not be a bug, but seems unintended.