Is it worth mentioning org-mode [0] and Racket's documentation system Scribble [1]. Docs as code and the tangle functionality in org-mode's Babel seem to fit right together. I am only familiar with Scribble by name.

[0] https://orgmode.org/manual/Working-with-Source-Code.html [1] https://docs.racket-lang.org/scribble/how-to-doc.html#%28par...