[MC-267629] Integer division of "enchantability" nullifies some of its intended advantages.

Enchantability is intended to describe an Item's propensity to receive rarer and higher level enchantments from the Enchanting Table. The greater the enchantability, the more likely the item will receive these enchantments.

The enchantability of all enchantable items ranks as follows:

Item	Enchantability
Golden Armor	25
Golden Tools	22
Netherite Armor and Tools Leather Armor Wooden Tools	15
Iron Tools	14
Chainmail Armor	12
Diamond Armor and Tools	10
Iron and Turtle Armor	9
Stone Tools	5
Other (e.g. Books)	1

In code, enchantability's intended function is achieved by modifying the enchantment level. However-before this is done-it is first integer divided by 4, then added to 1. This integer division truncates the differences between any two enchantabilities within the same modulus of 4, creating the following effective ranking:

Item	Effective Enchantability
Golden Armor	7
Golden Tools	6
Netherite Armor and Tools Leather Armor Wooden Tools Iron Tools Chainmail Armor	4
Diamond Armor and Tools Iron and Turtle Armor	3
Stone Tools	2
Other (e.g. Books)	1

As an example of the faulty results this causes, Netherite is intended to modify the enchantment level up to 25% greater than Chainmail (15 versus 12), yet their enchantabilities modify the enchantment level equally. At worst, this behavior nullifies the intended benefit of enchanting Netherite over Chainmail entirely. At best, it creates unnecessary computation.

A graphical demonstration can be found here:
https://www.desmos.com/calculator/pvu7whrb0g
where:

L = the enchantment level
E = (int) enchantability / 4
f( x ) = the probability distribution function of the modified enchantment level
x_i = a modified enchantment level, which is followed by the equation for the unweighted probability of achieving x_i