Corrects 200+ instances of "it's" where it should've been "its" instead (#85169)

## About The Pull Request

it's - conjunction of "it" and "is"
its - possessive form of "it"

grammar is hard, and there were a lot of places where "it's" was used
where it shouldn't have been. i went and painstakingly searched the
entire repository for these instances, spending a few hours on it. i
completely ignored the changelog archive, and i may have missed some
outliers. most player-facing ones should be corrected, though
## Why It's Good For The Game
proper grammar is good

## Changelog
🆑
spellcheck: Numerous instances of "it's" have been properly replaced
with "its"
/🆑

code/game/objects/structures/lavaland/geyser.dm

@@ -45,7 +45,7 @@
 
 ///start making those CHHHHHEEEEEEMS. Called whenever chems are removed, it's fine because START_PROCESSING checks if we arent already processing
 /obj/structure/geyser/proc/start_chemming()
-	START_PROCESSING(SSplumbing, src) //It's main function is to be plumbed, so use SSplumbing
+	START_PROCESSING(SSplumbing, src) //Its main function is to be plumbed, so use SSplumbing
 
 ///We're full so stop processing
 /obj/structure/geyser/proc/stop_chemming()

code/game/objects/structures/lavaland/ore_vent.dm

@@ -159,7 +159,7 @@
  * This proc is called when the ore vent is initialized, in order to determine what minerals boulders it spawns can contain.
  * The materials available are determined by SSore_generation.ore_vent_minerals, which is a list of all minerals that can be contained in ore vents for a given cave generation.
  * As a result, minerals use a weighted list as seen by ore_vent_minerals_lavaland, which is then copied to ore_vent_minerals.
- * Once a material is picked from the weighted list, it's removed from ore_vent_minerals, so that it can't be picked again and provided it's own internal weight used when assigning minerals to boulders spawned by this vent.
+ * Once a material is picked from the weighted list, it's removed from ore_vent_minerals, so that it can't be picked again and provided its own internal weight used when assigning minerals to boulders spawned by this vent.
  * May also be called after the fact, as seen in SSore_generation's initialize, to add more minerals to an existing vent.
  *
  * The above applies only when spawning in at mapload, otherwise we pick randomly from ore_vent_minerals_lavaland.