If you want a Mac app that does this, iA Writer has a feature called Syntax Control: https://ia.net/writer/updates/ia-writer-3-1-comes-in-colors https://ia.net/

If you want a Mac app that does this, iA Writer has a feature called Syntax Control: https://ia.net/writer/updates/ia-writer-3-1-comes-in-colors https://ia.net/writer/updates/ia-writer-3-1-comes-in-colors I use it sometimes, it works pretty well but occasionally gets confused.