makes it plausible to hear most sounds while inside of a VR sleeper (#8034)

code/modules/mob/living/living.dm

@@ -1067,10 +1067,12 @@
 		update_canmove() //if the mob was asleep inside a container and then got forceMoved out we need to make them fall.
 
 /mob/living/proc/update_z(new_z) // 1+ to register, null to unregister
+	if(isnull(new_z) && audiovisual_redirect)
+		return
 	if (registered_z != new_z)
 		if (registered_z)
 			SSmobs.clients_by_zlevel[registered_z] -= src
-		if (client)
+		if (client || audiovisual_redirect)
 			if (new_z)
 				SSmobs.clients_by_zlevel[new_z] += src
 				for (var/I in length(SSidlenpcpool.idle_mobs_by_zlevel[new_z]) to 1 step -1) //Backwards loop because we're removing (guarantees optimal rather than worst-case performance), it's fine to use .len here but doesn't compile on 511

code/modules/mob/mob.dm

@@ -76,6 +76,8 @@
 	return "a ... thing?"
 
 /mob/proc/show_message(msg, type, alt_msg, alt_type)//Message, type of message (1 or 2), alternative message, alt message type (1 or 2)
+	if(audiovisual_redirect)
+		audiovisual_redirect.show_message(msg ? "<avredirspan class='small'>[msg]</avredirspan>" : null, type, alt_msg ? "<avredirspan class='small'>[alt_msg]</avredirspan>" : null, alt_type)
 
 	if(!client)
 		return

code/modules/mob/mob_defines.dm

@@ -110,3 +110,5 @@
 	var/datum/click_intercept
 
 	var/registered_z
+
+	var/mob/audiovisual_redirect //Mob to redirect messages, speech, and sounds to