Move saddle from the treasure fishing category to the junk category

Now that the saddle has a crafting recipe, it is no longer as special as other treasure items, such as enchanted items or uncraftable items like name tags and nautilus shells. Therefore, the saddle should be moved from the 'treasure' category to the 'junk' category in fishing loot tables. In fact, its crafting cost is identical to leather boots, which makes perfect sense for it to share a similar category, albeit with a lower weight.