fine tuning the cython-linter + fix W391 code

[fchapoton]

• using just python 3.12
• removing E701 and E703, E302,E303,E306 from ignored, already fixed
• removing W391 too, fixed here

[oscarbenjamin]

Looks good. Thanks!

[oscarbenjamin]

Some of these could be fixed by the script mentioned https://github.com/flintlib/python-flint/pull/191#issuecomment-2317451322 which we should probably include as bin/lint_fix.py or something.