Racket v9.3

I do a substantial amount of coding in Racket, including maintaining the Herbie numerical compiler (https://herbie.uwplse.org/) over the last decade.

Racket is great! The runtime is reasonably fast, and the standard library is exceptionally featureful, including, for example, a decent plotting library, an HTTP server, decent HTML and JSON support, several forms of multi-threading, and a quite good FFI, all of which Herbie uses extensively. I suppose the parentheses are a question of taste (I like them!) but a lot of the specific syntactic decisions, like the `for` and `match` macros, are quite nice.