If a player or pet gets killed by an arrow (by summoning the arrow) the death message is "<Player> was slain by arrow"

To reproduce: (Reproduction steps given by Dr.Awesome4333)
1. Start a creative worldand place a cactus on some sand.
2. Change gamemode to survival
3. Use the cactus to lower HP to half a heart.
4. Summon an arrow with /summon ~ ~100 ~
Results: When you die the message reads:
"<player> was slain by arrow" in Bedrock
while in Java it reads:
"<player> was shot by arrow"