Rename OutlivesPredicate to OutlivesClause

[ada4a]

Follow-up to #160177

This is motivated by OutlivesPredicate being the inner type of ClauseKind::TypeOutlives and ClauseKind::RegionOutlives, and the "outlives clause" terminology already being used in a few places across the codebase.

One thing worth noting: OutlivesPredicate and its derivatives are duplicated in rustc_public. I chose to rename them, but leave the old names available as deprecated type aliases -- this should hopefully be semver-compatible?

r? @oli-obk
cc @nnethercote

[rustbot]

This PR changes rustc_public

cc @oli-obk, @celinval, @ouz-a, @makai410

rustc-dev-guide is developed in its own repository. If possible, consider making this change to rust-lang/rustc-dev-guide instead.

cc @BoxyUwU, @tshepang

HIR ty lowering was modified

cc @fmease

changes to the core type system

cc @lcnr