Allow categories to have a display name

src/game.lua

@@ -22,8 +22,8 @@ end
 
 function Game.get_stats(self, target)
 	local output = self.display_name .. " statistics of " .. target
-	for i, category in ipairs(self.categories) do
-		output = output .. "\n" .. category .. ": " .. self:get_stat(target, category)
+	for c_name, category in pairs(self.categories) do
+		output = output .. "\n" .. category.display_name .. ": " .. self:get_stat(target, c_name)
 	end
 	return true, output
 end