internal/abi: clean up type of Kind and Type.Kind_
Currently, Type.Kind_ is a uint8, Kind is a uint, and some of the
abi.Kind consts are not of type Kind. Clean this all up by making Kind
a uint8, then making Type.Kind a Kind, and finally making all Kind
consts actually have type Kind. This has some ripple effect, but I
think all of the changes are improvements.
Change-Id: If39be74699c2cdb52bf0ad7092d392bc8fb68d15
Reviewed-on: https://go-review.googlesource.com/c/go/+/575579
Auto-Submit: Austin Clements <austin@google.com> Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>