Fixed dual wield detection not working

Classes which cannot dual wield should no longer see (by default) orange text on offhand weapons that they would be able to equip if only the weapon was for main hand.

Config.lua

@@ -435,7 +435,7 @@ function Data:OnInitialize(L)
 
 
   function Data:IsUsable(itemType, itemSubType, invType)
-    return USABLE_EQUIPMENT[self.CLASS][itemType] and USABLE_EQUIPMENT[self.CLASS][itemType][itemSubType] and not UNUSABLE_INVTYPES[invType] and true or false
+    return USABLE_EQUIPMENT[self.CLASS][itemType] and USABLE_EQUIPMENT[self.CLASS][itemType][itemSubType] and not UNUSABLE_INVTYPES[self.CLASS][invType] and true or false
   end
 
   function Data:GetRedText(itemType, itemSubType, invType)