Fixed a playershelf shop issue with the multiple item feature not recognizing proper slot.

Bug Fix: Fixed a bug with player ShopShelves acting up on setting up items.

New Feature: Player ShopShelves now have a new setting (limit_playershelf_to_single_type) in the config by default on true if set to false it will allow players to use 3 different item types in 1 player ShopShelf.

Paper compatibility! My excuses for the wrong version!

My first upload was a spigot only plugin which i quickly fixed to have paper support i uploaded the second version correctly to modrinth but forgot to update spigot i am sorry for the inconvenience!