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/game/objects/items/implants/implant_chem.dm

@@ -38,7 +38,7 @@
 /obj/item/implant/chem/activate(cause)
 	. = ..()
 	if(!cause || !imp_in)
-		return 0
+		return
 	var/mob/living/carbon/R = imp_in
 	var/injectamount = null
 	if (cause == "action_button")

code/game/objects/items/implants/implant_mindshield.dm

@@ -59,8 +59,8 @@
 			L.sec_hud_set_implants()
 		if(target.stat != DEAD && !silent)
 			to_chat(target, "<span class='boldnotice'>Your mind suddenly feels terribly vulnerable. You are no longer safe from brainwashing.</span>")
-		return 1
-	return 0
+		return TRUE
+	return FALSE
 
 /obj/item/implanter/mindshield
 	name = "implanter (mindshield)"

code/game/objects/items/implants/implant_misc.dm

@@ -2,7 +2,7 @@
 	name = "firearms authentication implant"
 	desc = "Lets you shoot your guns."
 	icon_state = "auth"
-	activated = 0
+	activated = FALSE
 
 /obj/item/implant/weapons_auth/get_data()
 	var/dat = {"<b>Implant Specifications:</b><BR>
@@ -67,7 +67,7 @@
 
 /obj/item/implant/health
 	name = "health implant"
-	activated = 0
+	activated = FALSE
 	var/healthstring = ""
 
 /obj/item/implant/health/proc/sensehealth()

code/game/objects/items/implants/implantchair.dm

@@ -164,11 +164,11 @@
 
 /obj/machinery/implantchair/genepurge/implant_action(mob/living/carbon/human/H,mob/user)
 	if(!istype(H))
-		return 0
+		return FALSE
 	H.set_species(/datum/species/human, 1)//lizards go home
 	purrbation_remove(H)//remove cats
 	H.dna.remove_all_mutations()//hulks out
-	return 1
+	return TRUE
 
 
 /obj/machinery/implantchair/brainwash