This is my favorite syntax for technical writing, but unfortunately the only complete implementation is in Python. There are half-finished JS projects (last I checked) but nothing else. I really wish they were complete so we could use this in more places.

I opted for Djot (https://djot.net) as a second-place alternative with support for many more languages. My use case was attempting a Sphinx alternative in TypeScript. (Link for the curious: https://steveasleep.com/djockey/)