I think this will turn out well. Julia has had this forever as string macros, and it has worked out rather nicely, features like `r"\d+"` for regex, and `raw"st

I think this will turn out well. Julia has had this forever as string macros, and it has worked out rather nicely, features like `r"\d+"` for regex, and `raw"strings"` are just string macros. The set of all useful custom literal strings isn't bounded, so a lightweight mechanism to define them and make use of the results is a good thing. Another kitchen sink to add to Python's world-class kitchen sink collection.