A single unenchanted tool can be disenchanted in the grindstone

Summary

If a single unenchanted tool is placed into the input slot of a grindstone, the tool appears in the output slot and can be selected, even though the tool did not have any enchantments or need any repairs.

Steps to Reproduce:

1. Place down a grindstone.
2. Open the grindstone GUI.
3. Place a single unenchanted tool in the input slot.

Observed Results:

The tool appears in the output slot and can be selected despite it being unenchanted and fully repaired.

Expected Results:

The tool doesn't appear in the output slot and an "X" is placed over the arrow.