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/modules/surgery/organs/internal/lungs/_lungs.dm

@@ -537,7 +537,7 @@
 	n2o_euphoria = EUPHORIA_INACTIVE
 	breather.clear_alert(ALERT_TOO_MUCH_N2O)
 
-// Breath in nitrium. It's helpful, but has nasty side effects
+// Breathe in nitrium. It's helpful, but has nasty side effects
 /obj/item/organ/internal/lungs/proc/too_much_nitrium(mob/living/carbon/breather, datum/gas_mixture/breath, nitrium_pp, old_nitrium_pp)
 	breathe_gas_volume(breath, /datum/gas/nitrium)