Add naming parameters for [hasitem] in inventory.

This really should’ve been included when [hasitem] was implemented. The game can already recognize an item based on its name when the item is a floating entity outside of the players inventory. There’s really no reason why “/effect @a [hasitem={item=bow,name=youruniqueitemname,location=slot.weapon.mainhand}]” doesn’t work. It seems like it would be super easy to add the parameter to the command system. 😭