TracebackException subclass

It would be useful to have a [TracebackException](https://docs.python.org/3/library/traceback.html#traceback.TracebackException) subclass that added column information, perhaps also with a default `format` override. That way existing code that uses the `traceback` module could easily swap it out for something that shows column information. It might also be useful to have versions of the various functions in the `traceback` module that used this.