HN actually does support markdown code blocks, you just have to preface lines with four (nope, two)[1] spaces instead of the (newer) triple-backtick codefences.

  ID,NAME,DATE
  "/^\d+$/","//","/^\d{4}-\d{2}-\d{2}$/"
  867,Alice,1984-01-09
  5309,Bob,1981-11-16

[1] apparently it's actually two spaces instead of the normal markdown standard of four, making HN even more non-standard than usual

https://news.ycombinator.com/formatdoc