[MIRROR] Adds defines for mouse_opacity (#2381)

* Adds defines for mouse_opacity

* Delete misc.dm.rej

* Update misc.dm

code/modules/projectiles/guns/beam_rifle.dm

@@ -714,7 +714,7 @@
 	light_power = 1
 	light_range = 2
 	light_color = "#00ffff"
-	mouse_opacity = 0
+	mouse_opacity = MOUSE_OPACITY_TRANSPARENT
 	flags = ABSTRACT
 	appearance_flags = 0
 

code/modules/projectiles/projectile.dm

@@ -6,7 +6,7 @@
 	anchored = TRUE
 	flags = ABSTRACT
 	pass_flags = PASSTABLE
-	mouse_opacity = 0
+	mouse_opacity = MOUSE_OPACITY_TRANSPARENT
 	hitsound = 'sound/weapons/pierce.ogg'
 	var/hitsound_wall = ""