fix: adding to empty slot and max_stack_size

[CuzImClicks]

Fixes try_add_to_slot creating stacks above the maximum stack size when adding to an empty slot

[CuzImClicks]

also while working on the give command i noticed that the try_add_item method doesn't work correctly because it also fills the 2x2 crafting and armor slots. is there a reason why try_add_to_slot is private btw?

[andrewgazelka]

is there a reason why try_add_to_slot is private btw?

not really