Toggle position of items in shelves by shift-right clicking.

On the latest Minecraft Java's snapshot, the position of items in shelves was reverted to be on the middle. I personally see this as a positive, but I thought of a way to make both the players who prefer to have their items located at the bottom of the shelves and the players that prefer the items in the middle, and it's to make the position togglable by right clicking the shelve while shifting.