feature/enhancement: support ob_next and ob_prev when built with Py_TRACE_REFS

[mqyhlkahu]

Py_TRACE_REFS can be dynamically detected, because it defines sys.getobjects. At import time, you could check for sys.getobjects and define the extra members on the PyObject struct if it's present.

[mqyhlkahu]

Note: if this feature is added, it would only apply to python version <= 3.12 -- ob_next and ob_prev are present in 3.12 (if built with the right option) but don't seem to be present in the main branch (3.13).