Quickstow

Adds a keybind (V by default) to move your active item (right hand) to your inventory in the first open slot.

Works the same as opening the inventory and shift clicking and will stack the stowed item with the same already in inventory if there is any. 
Sends a message in chat if your inventory is full. Works while inventory is open as well, as an alternative to shift-click.

Keybind can be changed in the control menu.

This is a client side mod, useful for putting a tool away or just getting an empty hand when needed. If you use a mining bag, I'd recommend putting it in your backpack slot so it can catch pickaxes.

Not much more to say really. Couldn't figure out how to implement an undo while keeping it purely client side.

Testing shows this works on 1.22.3.