[1.21.x] Make RenderPlayerEvent subclass RenderLivingEvent

[dhyces]

Closes #1266

Shouldn't introduce breaking changes other than binary breaks. Also took the opportunity to clean up some of the docs that referenced now removed features, like GenericEvents and HasResult, and renamed "Forge event bus" references to "game event bus".

[neoforged-pr-publishing]

• Publish PR to GitHub Packages

[neoforged-compatibility-checks]

@dhyces, this PR introduces breaking changes.
Fortunately, this project is currently accepting breaking changes, but if they are not intentional, please revert them.
Last checked commit: fd90f489c0df3307aba250338fb12e147790220c.

neoforge (:neoforge)

• net/neoforged/neoforge/client/event/RenderPlayerEvent
  • ❗ Class missing superclass of net/neoforged/neoforge/event/entity/player/PlayerEvent

[TelepathicGrunt]

Putting a 1.21.1 tag on this PR. It is a bit too late now to move events around. We can revisit this PR on next breaking mc version. Or if you adjust this PR to only be javadoc cleanup, we can merge that and have an issue report or something to do the event moving in future mc version

[dhyces]

Understandable. I don't think the jdoc changes are important enough to warrant a separate PR just for these two classes. imo, they should either be fixed in bulk or modified when the classes are changed.