use SIGNAL_HANDLER REEEEEE (#59242)

makes as many procs as i can find use the SIGNAL_HANDLER define which i assumed they all already did

code/game/objects/items/devices/PDA/PDA.dm

@@ -1262,6 +1262,7 @@ GLOBAL_LIST_EMPTY(PDAs)
 		. += P
 
 /obj/item/pda/proc/pda_no_detonate()
+	SIGNAL_HANDLER
 	return COMPONENT_PDA_NO_DETONATE
 
 #undef PDA_SCANNER_NONE

code/game/objects/items/devices/geiger_counter.dm

@@ -37,7 +37,7 @@
 /obj/item/geiger_counter/Destroy()
 	STOP_PROCESSING(SSobj, src)
 	QDEL_NULL(soundloop)
-	
+
 	return ..()
 
 /obj/item/geiger_counter/process(delta_time)
@@ -211,6 +211,7 @@
 	listeningTo = user
 
 /obj/item/geiger_counter/cyborg/proc/redirect_rad_act(datum/source, amount)
+	SIGNAL_HANDLER
 	rad_act(amount)
 
 /obj/item/geiger_counter/cyborg/dropped()

code/game/objects/items/devices/megaphone.dm

@@ -29,6 +29,7 @@
 	UnregisterSignal(M, COMSIG_MOB_SAY)
 
 /obj/item/megaphone/proc/handle_speech(mob/living/carbon/user, list/speech_args)
+	SIGNAL_HANDLER
 	if (user.get_active_held_item() == src)
 		if(spamcheck > world.time)
 			to_chat(user, "<span class='warning'>\The [src] needs to recharge!</span>")

code/game/objects/items/devices/radio/intercom.dm

@@ -120,6 +120,7 @@
  * * source - the area that just had a power change.
  */
 /obj/item/radio/intercom/proc/AreaPowerCheck(datum/source)
+	SIGNAL_HANDLER
 	var/area/current_area = get_area(src)
 	if(!current_area)
 		on = FALSE