bug#56757: 29.0.50; Python f-string font-lock logic is incomplete

[Lars Ingebrigtsen]

Laurence Warne <laurencewarne@gmail.com> writes:

> Hi, I've attached a patch which looks good to me locally using the above 
> examples
> and others.
>
> In addition to the above, mixed capitalizations are also covered:
> https://docs.python.org/3/reference/lexical_analysis.html#string-and-bytes-literals.

I think your patch makes sense, but it leads to failures in:

1 unexpected results:
   FAILED  python-font-lock-escape-sequence-multiline-string

Could you have a look at that and possibly adjust the test too (if it's
the test that's wrong here)?