Bools and returns super-pr (#53221)

Replaces like 70-80% of 0 and such, as a side effect cleaned up a bunch of returns
Edit: Most left out ones are in mecha which should be done in mecha refactor already
Oh my look how clean it is

Co-authored-by: TiviPlus <TiviPlus>
Co-authored-by: Couls <coul422@gmail.com>

code/modules/client/verbs/suicide.dm

@@ -1,4 +1,4 @@
-/mob/var/suiciding = 0
+/mob/var/suiciding = FALSE
 
 /mob/proc/set_suicide(suicide_state)
 	suiciding = suicide_state
@@ -22,7 +22,7 @@
 			mmi.brainmob.suiciding = suicide_state
 
 /mob/living/carbon/human/verb/suicide()
-	set hidden = 1
+	set hidden = TRUE
 	if(!canSuicide())
 		return
 	var/oldkey = ckey