Enchanted books on lecterns will make Librarians trade for it.

Although I enjoy how Librarians work to bring in different book enchantments, I think that it has made it way too easy to gain high-tier ones. It makes getting the best enchantments in the game feel unrewarding and stale beyond just 'rolling a lucky number' when placing a lectern. 

To improve this I propose an idea where Librarians will only roll enchantments up to level III instead. In order for the Librarian to trade for a higher enchantment, the player would need to first craft or find their desired one and place it on a new Librarian's lectern. It's like he's learning from the book.

This would also come with a price increase for level III enchantments, becoming as expensive as level 4 or 5 enchantments. wdyt?