Changes

Downgrade NMS revision

This is not a precedent, please see https://www.spigotmc.org/wiki/nms/

SPIGOT-6205: Rewrite enum to/from NMS type methods

The methods would otherwise cache wrong enum types for specific enums.
This would result in a `ClassCastException` at the caller location,
which obviously is no fun. This broke API with `Switch#getFace` and
`FaceAttachable#getAttachedFace`.

The existing implementation was also stupid.