Racket v8.17

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• The new drracket-core package provides a version of drracket with a smaller set of dependencies.
• Typed Racket has support for treelists.
• The package manager computes checksums for packages when required, allowing the use and automatic upgrade of packages without them.
• The bitwise-first-bit-set function returns the smallest bit that is set in the twos-complement representation of the given number.
• The updated dynamic-require function makes it easier to use syntax bindings by allowing a syntax-thunk (or 'eval) to be used for them.
• The error-module-path->string-handler parameter allows the customization of the display of module-paths in error messages.
• Precision of certain numeric functions (sin, cos, and others) is improved on Windows platforms by using the MSVCRT/UCRT libraries.
• The string-append function has improved performance and reduced memory use for long lists of strings in the Racket CS implementation. Differences are clearly noticeable for lists of length 1 million.
• TCP ports use SO_KEEPALIVE, instructing the kernel to send periodic messages while waiting for data to check whether the connection is still responsive.
• Racket code using a terminal in Windows can receive mouse events as virtual terminal characters after using SetConsoleMode. (This is also already possible on macOS and Linux.) See the tui-term package for related example code.
• The #:replace-malformed-surrogate? keyword can be used to specify a replacement for malformed unicode surrogates in JSON input
• The http-client module no longer sends "Content-Length: 0" for requests without a body.
• The demodularizer (compiler/demod) can prune more unused assignments.
• Several judgment rendering forms in Redex are replaced by functions, allowing more convenient abstraction.
• When a distribution includes no teaching languages, DrRacket’s language-dialog configuration moves into the preferences dialog and the “Language” menu disappears.
• The math library has better support for block-diagonal matrices, including both Racket and Typed Racket.
• The math library contains improved implementations of acos and matrix-(cos-)angle.
• The stepper again works for big-bang programs.
• There are many other repairs and documentation imprevements!

The following people contributed to this release:

Alexander Shopov, Andrei Dorian Duma, Bert De Ketelaere, Bob Burger, Bogdan Popa, Bogdana Vereha, Cameron Moy, Chung-chieh Shan, Cutie Deng, D. Ben Knoble, Dario Hamidi, Dominik Pantůček, Gustavo Massaccesi, halfminami, Jacqueline Firth, Jason Hemann, Jens Axel Søgaard, Joel Dueck, John Clements, Jordan Harman, Marc Nieper-Wißkirchen, Matthew Flatt, Matthias Felleisen, Mike Sperber, Noah Ma, owaddell-ib, Philippe Meunier, Robby Findler, Ryan Culpepper, Ryan Ficklin, Sam Phillips, Sam Tobin-Hochstadt, Shu-Hung You, sogaiu, Sorawee Porncharoenwase, Stephen De Gabrielle, Vincent Lee, and Wing Hei Chan.

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