Grouping options does not work with padding inside

[Carbon based Guibou]

In python:

>>> f"{0:0=#10_b}"
'0b000_0000

In PyF:

> [f'|{0:0=#10_b}|] :: String
"0b00000000"

[Carbon based Guibou]

Actually it onl works if the padding value is 0.

[Carbon based Guibou]

This is super weird actually ;)

In python, the semantic is interesting:

>>> f"{0:~=#10_b}"
'0b~~~~~~~0'
>>> f"{0:0=#10_b}"
'0b000_0000'