Renamed the texture of the warrior armor, update spreadsheet

Add the shield black mithril plated armor

mods/3d_armor/shields/init.lua

@@ -100,6 +100,15 @@ if ARMOR_MATERIALS.mithril then
 	})
 end
 
+if ARMOR_MATERIALS.black_mithril then
+	minetest.register_tool("shields:shield_black_mithril_warrior", {
+		description = "Black Mithril Shield",
+		inventory_image = "shields_inv_shield_mithril.png",
+		groups = {armor_shield=15, armor_heal=2, armor_use=50},
+		wear = 0,
+	})
+end
+
 if ARMOR_MATERIALS.crystal then
 	minetest.register_tool("shields:shield_crystal", {
 		description = "Crystal Shield",