build: enable refurb rules in ruff

[coveralls]

coverage: 99.822%. remained the same when pulling 5fe1827e5343292ba53c83be30056dd2370551f0 on DimitriPapadopoulos:refurb into d20aa6d30299575ed60fcd6ba1d2cd741555550e on adrienverge:master.

[adrienverge]

I'm not of than of these rules. Sometimes it helps readability to be able to write what refurb dislikes.

[DimitriPapadopoulos]

Agreed. Some of the rules do improve code and performance, other rules may result in less readable code, such as:

if ...:
    return ....
return ....

instead of:

if ...:
    return ....
else:
    return ....