Adds a new ghost vis blocking area flag (#16696)

* Adds a new ghost vis blocking area flag

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* add admin verbs to add and remove areas

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code/modules/materials/materials/gems.dm

@@ -50,8 +50,8 @@
 
 /datum/material/quartz
 	name = MAT_QUARTZ
-	display_name = "quartz"
-	use_name = "quartz"
+	display_name = MAT_QUARTZ
+	use_name = MAT_QUARTZ
 	icon_colour = "#e6d7df"
 	stack_type = /obj/item/stack/material/quartz
 	tableslam_noise = 'sound/effects/Glasshit.ogg'

code/modules/materials/sheets/glass.dm

@@ -1,7 +1,7 @@
 /obj/item/stack/material/glass
-	name = "glass"
+	name = MAT_GLASS
 	icon_state = "sheet-transparent"
-	default_type = "glass"
+	default_type = MAT_GLASS
 	no_variants = FALSE
 	drop_sound = 'sound/items/drop/glass.ogg'
 	pickup_sound = 'sound/items/pickup/glass.ogg'