There are tools to do exactly that, like a simple bash scripts lit.sh: https://github.com/vijithassar/lit

Pandoc is a nice swiss army knife that can do a similar conversion with some custom lua filters. It could even do wackier stuff like convert word or odt files to code if you were really diving into prose-first coding.

I've also heard it referred to as 'semi-literate programming' because it skips the reorganization functionality and just gives you nice prose to code conversion.