Fix EffKill failing to kill entities

[bluelhf]

Problem

Currently, using the kill effect to cause an entity to die does not guarantee that the entity dies. In server versions where damage sources are supported, Skript attempts to deal a high amount of damage (100 hearts plus twice the hearts of the entity being killed). However, if an event listener reduces the damage to a number lower than the entity's health, then the entity does not die.

For entities other than players, the effect correctly remove()s the entity if they fail to die. However, since removing players is not possible (throws UnsupportedOperationException), they are exempt from this last-ditch effort, and end up not dying at all.

The bug, also described in #8441, can be reproduced with this code:

command /slay:
  trigger:
    kill player

on damage:
  set damage to 0.01 * damage
  send "Reduced damage is %damage%, your health is %2 * victim' health%" to victim

Without this PR, the /slay command does not kill the player. With the addition of this PR, /slay kills the player correctly.

Solution

This PR fixes the issue by dealing Double.POSITIVE_INFINITY damage instead, which event listeners are more likely to handle correctly.

It is impossible to fix the root cause of the problem without changing the Paper API to implement a proper kill() method that bypasses event listeners. It should be noted that for living entities, /minecraft:kill behaves identically to the new implementation added in this PR.

Testing Completed

Verified that the PR fixes the issue using the aforementioned script

Supporting Information

Before PR	After PR

---

Completes: #8441
Related: none
AI assistance: none

[sovdeeth]

Can you confirm this doesn't apply crazy amounts of durability damage to armor? I don't think it should but better to double check.

[bluelhf]

Can you confirm this doesn't apply crazy amounts of durability damage to armor? I don't think it should but better to double check.

It does not, since the minecraft:generic_kill damage type has tag #minecraft:bypasses_armor

It also bypasses resistance, invulnerability (incl. totems of undying), and knockback

[APickledWalrus]

Adding label pending confirmation of the issue being fixed by the reporting user