It's hardly a rare feature. Everything from C# to JS has it these days, so I think "out of reach of most syntax highlighting tools" might be overstating things

It's hardly a rare feature. Everything from C# to JS has it these days, so I think "out of reach of most syntax highlighting tools" might be overstating things a bit. It can't be that hard. You don't have to allow nested strings either; Python's f-strings don't, they always parse as a regular string too (well, you can use a 'single-quoted string' inside a "double-quoted f-string").