Convert /material to it's correct absolute path /datum/material (#7637)

code/game/objects/items/stacks/stack.dm

@@ -169,7 +169,7 @@
 		if ((pass_color || recipe.pass_color))
 			if(!color)
 				if(recipe.use_material)
-					var/material/MAT = get_material_by_name(recipe.use_material)
+					var/datum/material/MAT = get_material_by_name(recipe.use_material)
 					if(MAT.icon_colour)
 						O.color = MAT.icon_colour
 				else

code/game/objects/items/weapons/material/material_armor.dm

@@ -27,7 +27,7 @@ Protectiveness | Armor %
 
 // Putting these at /clothing/ level saves a lot of code duplication in armor/helmets/gauntlets/etc
 /obj/item/clothing
-	var/material/material = null // Why isn't this a datum?
+	var/datum/material/material = null // Why isn't this a datum?
 	var/applies_material_color = TRUE
 	var/unbreakable = FALSE
 	var/default_material = null // Set this to something else if you want material attributes on init.

code/game/objects/items/weapons/material/material_weapons.dm

@@ -24,7 +24,7 @@
 	var/thrown_force_divisor = 0.5
 	var/dulled_divisor = 0.5	//Just drops the damage by half
 	var/default_material = DEFAULT_WALL_MATERIAL
-	var/material/material
+	var/datum/material/material
 	var/drops_debris = 1
 
 /obj/item/weapon/material/New(var/newloc, var/material_key)