Minor cleanups to compiler.
Add caching for collects-relative->path.
Add TR helpers for new Racket error notation
Convert check-below.rkt error msgs to new format
fix bad interaction among JIT, 3-D macro, and bytecode reader

Closes PR 14186
fix (more) closure type tracking for a procedure with only an unused rest arg

Fixs the repair in fe12a32dc3

Relevant to PR 14259
Add a #lang for additional base type environments

These are for base type environments that get required
rather than loaded with #lang typed/racket.
Add types for `syntax/stx` as `typed/syntax/stx`
Refine handling of types for struct-types

  - Added a top type for struct-types
  - Print struct-type types consistently
  - Add support for parsing struct-types
  - Allow polymorphism within a Struct-Type
Improve base types for struct-type operations
Add tests for struct-type types
Add documentation for struct-type types
Fix broken TR test

Sorry, forgot to merge this into commit
892887b before pushing the last set of changes.