Adventure 5.0

[kezz]

Introduction

This PR exists to track the progress on Adventure 5.0. It only exists as a PR for review purposes, once Adventure 5.0 is complete, the main branch of the repo will be changed to main/5.

Discussion in this PR will be limited to reviews of the PR itself. For discussion about broader changes in Adventure 5.0, please see #1202.

To-do list:

The list below tracks remaining tasks. For reference, "refactor" means removal of all deprecations and refactoring of code to use modern Java language features.

• Bump Java version to 21.
• Refactor annotation-processors module.
• Refactor api module.
• Remove extra-kotlin module.
• Refactor key module.
• Refactor nbt module.
• Refactor serializer-configurate-4 module.
• Refactor text-logger-slf4j module.
• Refactor text-minimessage module.
• Refactor text-serializer-ansi module.
• Refactor text-serializer-commons module.
• Refactor text-serializer-gson module.
• Refactor text-serializer-gson-legacy-impl module.
• Refactor text-serializer-json module.
• Refactor text-serializer-json-legacy module.
• Refactor text-serializer-legacy module.
• Refactor text-serializer-plain module.
• Fix GitHub actions builds.
• Check all Javadocs, IJ's reformatting changes JD references to impl classes and fucks up spacing for no reason

4.0 deprecations/changes

• Deprecate Buildable interface

Add ApiStatus.NonExtendible to:

• Title.Times
• Sound.Builder
• ResourcePackRequest (and Builder)
• ResourcePackInfo (and Builder)
• PointersSupplier (and Builder)
• Pointers (and Builder)
• Pointer
• Identity
• ComponentFlattener (and Builder)

Remaining discussion points

• Do we bump to Java 25 upon release?
• Look at other features targeted for 5.0 release.
• Migrate to Jspecify?
• Do we want to type click event?
• Decide if we want Examinable to be public API or not
  atm it's literally just used for toString, but is sometimes in the API classes and sometimes impl only - we should be consistent here