19423b5944
even more unify Projection/Opaque handling in region outlives code edit: This continues ate the same pace as #106829. New changes are described in https://github.com/rust-lang/rust/pull/106910#issuecomment-1383251254. ~This touches `OutlivesBound`, `Component`, `GenericKind` enums.~ r? `@oli-obk` (because of overlap with #95474)
For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.