Toggle ghost now leaves the users mob visible (#6065)

# About the pull request
Fixes #5894

# Explain why it's good for the game
bug fix

# Changelog
:cl:
fix: toggling ghost vision now keeps the user's mob visible.
/:cl:

---------

Co-authored-by: DOOM <N/A>

code/__DEFINES/__game.dm

@@ -78,6 +78,8 @@
 #define SEE_INVISIBLE_LEVEL_TWO 45 //Used by some other stuff in code. It's really poorly organized.
 #define INVISIBILITY_LEVEL_TWO 45 //Used by some other stuff in code. It's really poorly organized.
 
+#define HIDE_INVISIBLE_OBSERVER 59 // define for when we want to hide all observer mobs.
+
 #define INVISIBILITY_OBSERVER 60
 #define SEE_INVISIBLE_OBSERVER 60
 

code/modules/mob/dead/observer/observer.dm

@@ -37,6 +37,7 @@
 	/// If the observer is an admin, are they excluded from the xeno queue?
 	var/admin_larva_protection = TRUE // Enabled by default
 	var/ghostvision = TRUE
+	var/self_visibility = TRUE
 	var/can_reenter_corpse
 	var/started_as_observer //This variable is set to 1 when you enter the game as an observer.
 							//If you died in the game and are a ghost - this will remain as null.
@@ -71,10 +72,10 @@
 	set desc = "Toggles your ability to see things only ghosts can see, like other ghosts"
 	set category = "Ghost.Settings"
 	ghostvision = !ghostvision
-	if(hud_used)
-		var/atom/movable/screen/plane_master/lighting/lighting = hud_used.plane_masters["[GHOST_PLANE]"]
-		if (lighting)
-			lighting.alpha = ghostvision? 255 : 0
+	if(ghostvision)
+		see_invisible = INVISIBILITY_OBSERVER
+	else
+		see_invisible = HIDE_INVISIBLE_OBSERVER
 	to_chat(usr, SPAN_NOTICE("You [(ghostvision?"now":"no longer")] have ghost vision."))
 
 /mob/dead/observer/Initialize(mapload, mob/body)
@@ -845,11 +846,12 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 /mob/dead/observer/verb/toggle_self_visibility()
 	set name = "Toggle Self Visibility"
 	set category = "Ghost.Settings"
-
-	if (alpha)
-		alpha = 0
-	else
+	self_visibility = !self_visibility
+	if (self_visibility)
 		alpha = initial(alpha)
+	else
+		alpha = 0
+	to_chat(usr, SPAN_NOTICE("You are now [(self_visibility?"visible":"invisible")]."))
 
 /mob/dead/observer/verb/view_manifest()
 	set name = "View Crew Manifest"