EventValues - add an option to use changers

[ShaneBeee]

Description

This PR aims to add the ability to have changers for event-values.

NOTES:

• I extended from converter, EventConverter, this will have the same things a converter has plus the option to set.
• I only added "set" as I figured other changers (reset, delete, add, remove, etc) would just end up clogging up the EventValues class. If someone needs more changers, that would be a great time to create an expression.
• The EventValueExpression class scared me... I'm not 100% sure if I did this in the nicest way possible (Feedback would be appreciated here)
• I added an example for event-item in the consume event. TESTED HEAVILY with both a single value and array. Works nicely.

---

Target Minecraft Versions: any
Requirements: none
Related Issues: #7485

[ShaneBeee]

Showcase:

on consume:
	send "Before: %event-item%"
	set event-item to 1 of stick
	send "After: %event-item%"

Screen.Recording.2025-01-22.at.10.42.50.PM.mov

[APickledWalrus]

The code itself seems fine. I'm wondering how this might interact with existing event value expressions, such as https://github.com/SkriptLang/Skript/blob/master/src/main/java/ch/njol/skript/expressions/ExprItem.java. It appears there would be a difference with set the item to ... and set the event-item to ...

[ShaneBeee]

The code itself seems fine. I'm wondering how this might interact with existing event value expressions, such as https://github.com/SkriptLang/Skript/blob/master/src/main/java/ch/njol/skript/expressions/ExprItem.java. It appears there would be a difference with set the item to ... and set the event-item to ...

I'll be honest, this didn't cross my mind. Ill test and get back to you.

EDIT:
As per video/code sent in DM on discord, the item expression still works as it should.

[NotSoDelayed]

Room for adding JUnit tests? (Expecting to exceed beyond the limit of the sky)