Kudzu Rebalances v2 (#66295)

Increases kudzu's maximum mutation severity to 25 from 20.
Event-spawned kudzu now will have a flat +10 bonus to its maximum severity, meaning that it'll now range from 27 to 35 to compensate for it not being manually made.
Explosive kudzu mutation is now classified as maximum severity.
New "Temperature stabilisation" SEVERITY_AVERAGE mutation as a compensation for coldmos and the worry that cold environments can be too harsh to kudzu without the coldproof mutation by offering another alternative. It has the same power as the space heater at 40000J per atmos tick (101.325 kPa of air mix at 293.15K has 2079J/C of heat capacity, so around 20C change to that turf per atmos tick, even larger if its depressurised).
Nerfs the venus human trap's vine throw by making it have the cooldown of a regular baton (4 seconds vs previously 3), since the knockdown is only 1 second long this should be fair in exchange for keeping the 85 stamina damage in.
Doubles the mutativeness scale factor, meaning that the probability of kudzu mutating in general has been doubled.
Also adds some previously missing #undef's at the end of the file.

NEW CHANGES:
Kudzu spread rate has been changed, event kudzu is now guaranteed to spread at least 3 times per second (which is now actually adjusted for delta_time), and in general kudzu now gets a boost when it just spawned to help it not die instantly. A graph of the new formula is https://www.desmos.com/calculator/ynvbzspkmo.
Slightly more documentation to some of kudzu's variables

code/modules/mob/living/simple_animal/hostile/venus_human_trap.dm

@@ -128,6 +128,7 @@
 	melee_damage_upper = 20
 	minbodytemp = 100
 	combat_mode = TRUE
+	ranged_cooldown_time = 4 SECONDS
 	del_on_death = TRUE
 	deathmessage = "collapses into bits of plant matter."
 	attacked_sound = 'sound/creatures/venus_trap_hurt.ogg'