Allow to harvest multiple crops at once in a flat square centered on the right-clicked crop.

Config option to choose whether at which kind of hoe multiple harvest can happen, setting it to the lowest possible value (0, -1, 'none', I'll see) allows multiple harvests to happen without a hoe.
Default to wooden hoe? stone? iron?

Config option to choose whether the multiple harvest area should increment with the hoe level, e.g. wood 2x2, stone 3x3, iron 4x4, and so on, or fixed, e.g. all the same.
It will scale based on the starting hoe level: the starting one will always be a 2x2, then the next one a 3x3, etc.
For example with this kind of config:

min hoe level = iron
should increment = true

only hoes with a iron level or higher will allow multiple harvest, with iron hoes harvesting in a 2x2 square, a diamond in a 3x3, a netherite in a 4x4.

Changes in the API and its wiki.

What about shifting? Currently shifting disables right-click harvest, but what should happen with multiple harvest? Still disabled, or harvesting just 1 crop?