Feature or enhancement

Add %X (uppercase hex) format to PyUnicode_FromFormat().

Pitch

%X's omission is not intentional, it was just not needed so far. There are many cases where it would be useful, for example the canonical representation of Unicode code points (f"U+{code:0>4X}").

Previous discussion

https://discuss.python.org/t/pyunicode-fromformat-add-x