Double Jump Boots

This mod adds double jump boots to the game! (using jump boost potions is OP) this can help with PvP, jumping, building etc. people always wanted to have this, I made this an item not an effect! (Bug: there is a bug if you have it in your inventory without wearing then the effect applies! this is unintended, I'm trying to code something to stop the bug, if someone can code a bugfix then please do! I'm new to modding!)