Rollup merge of #110220 - lcnr:regionzz, r=compiler-errors

cleanup our region error API

- require `TypeErrCtxt` to always result in an error, closing #108810
- move `resolve_regions_and_report_errors` to the `ObligationCtxt`
- call `process_registered_region_obligations` in `resolve_regions`
- move `resolve_regions` into the `outlives` submodule
- add `#[must_use]` to functions returning lists of errors

r? types

Author: matthiaskrgr