Release Announcement for v9.3

Internals
1 
The release announcement sketch that I have so far is below.  Please
mail me new items and/or edits.

Please phrase announcements using complete sentences and avoid the
word "now".

As of this release:

  • The raco setup command can generate markdown documentation, using the --doc-markdown option.
  • A number of changes address the teaching "#lang" teaching languages, the ones chosen by the use of a "#lang" first line in conjunction with the "The Racket Language" selection in the Language dialog:
    • These languages can specify DrRacket annotation values, to enable test coverage by default.
    • These languages display coverage information by default in DrRacket.
    • These languages display source-code locations in the same way as the menu-based *SL languages.
  • DrRacket's background expansion disables errortrace annotations, for faster syntax checking.
  • The raco pkg install command includes new options that provide more install-time configuration flexibility: --adjacent-deps, --destdir, and --attach, and a refined --skip-installed.
  • The ffi/unsafe/runtime-lib library provides a define-runtime-lib mechanism similar to define-runtime-path, allowing location of libraries located relative to a source file.
  • The prompt-tag/c contract generator no longer performs checking on call/cc when the #:call/cc option is not present.
  • The impersonate-prompt-tag function takes an additional argument that allows checking and update of results for composable continuations.
  • The error-syntax->srcloc-handler parameter provides control over the mapping from syntactic forms to source locations for error handling.
  • Uses of (tcp-listen 0) will retry when it fails with "address in use".
  • The racket/base module requires fewer internal modules and instantiations.
  • The file/zip package provides a new mechanism for greatly increased control over zip file generation, allowing in-memory file sources and per-file compression control.

Link to pkg-build regressions / blockers issue: Release Regressions for 9.3 · Issue #5546 · racket/racket · GitHub