parser: add support for f-strings

[shellquery]

File "/opt/homebrew/Cellar/python@3.9/3.9.20/Frameworks/Python.framework/Versions/3.9/lib/python3.9/json/init.py", line 339, offset 80
raise TypeError(f'the JSON object must be str, bytes or bytearray, '

SyntaxError: 'invalid syntax'

[sbinet]

yeah, gpython is (quoting the README) a part re-implementation, part port of the Python 3.4 interpreter in Go.
IIRC, f-strings were not yet in (if memory serves, they were brought in CPython 3.6).

we'd be happy to review a PR adding this feature :}