It's not really a solved problem in general. Most editors appear to use TextMate grammars which nobody likes. Otherwise you have to implement it using whatever

It's not really a solved problem in general. Most editors appear to use TextMate grammars which nobody likes. Otherwise you have to implement it using whatever custom setup your specific editor uses. It just happens that most languages have some poor soul who set this up already. Emacs is actually on the better side because tree-sitter is a much better setup for writing grammars.