Update tp_finalize example to use PyErr_GetRaisedException

[cmaloney]

Documentation

The tp_finalize C API doc currently uses the older PyErr_Fetch + PyErr_Restore API to stash the current exception in its sample implementation. That API was deprecated in 3.12.

Update the example to use the suggested replacement PyErr_GetRaisedException and PyErr_SetRaisedException

Linked PRs

• gh-131117: Update tp_finalize example to use PyErr_GetRaisedException #131118