Updates item storages documentation (#4937)

* Updates the documentation for the different types of player item storages to reflect that current maximum capacity.
Thanks to @sader1992!

src/common/mmo.hpp

@@ -377,7 +377,7 @@ struct s_storage {
 		unsigned get : 1;
 		unsigned put : 1;
 	} state;
-	union { // Max for inventory, storage, cart, and guild storage are 1637 each without changing this struct and struct item [2014/10/27]
+	union { // Max for inventory, storage, cart, and guild storage are 818 each without changing this struct and struct item [2016/08/14]
 		struct item items_inventory[MAX_INVENTORY];
 		struct item items_storage[MAX_STORAGE];
 		struct item items_cart[MAX_CART];