Add death types support to the Lua Kill() API.

[pchote]

Fixes #18169.

Adding this to the milestone because @Smittytron has another ant mission ready to PR that depends on this (which i'd like to get into the playtest too), and it sounds like we can also use this to fix a polish bug in Sarin Gas 2 (if someone can tell me the changes i'll add them here).

Testcase: add the following snippet to the bottom of SendInsertionHelicopter in mods/ra/maps/allies-01/allies01.lua and uncomment each case to test:

Trigger.AfterDelay(DateTime.Seconds(4), function()
	tanya.Kill()
	--tanya.Kill("FireDeath")
	--tanya.Kill({"FireDeath", "Incendiary"})
end)

[Smittytron]

Works.

and it sounds like we can also use this to fix a polish bug in Sarin Gas 2 (if someone can tell me the changes i'll add them here).

That'll be "ExplosionDeath" on line 116.

[pchote]

Updated Sarin Gas 2 and also Top o' the World. These are the only two missions I can see that use .Kill() on infantry.

[abcdefg30]

Changelog

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