[3.12] gh-102304: Fix Py_INCREF() for limited C API 3.9 (#105553)

* gh-102304: Fix Py_INCREF() for limited C API 3.9 (#105550)

When Python is built in debug mode (Py_REF_DEBUG macro), Py_INCREF()
and Py_DECREF() of the limited C API 3.9 (and older) now call
Py_IncRef() and Py_DecRef(), since _Py_IncRef() and _Py_DecRef() were
added to Python 3.10.

(cherry picked from commit 7ba0fd9f87ad75f8eda8e002c2fc71049b815f33)

* gh-102304: Remove Py_INCREF() doc change (#105552)

Py_INCREF() was made compatible again with Python 3.9 and older in
the limited API of Python debug mode.

(cherry picked from commit 58e4b69f698e6fd0694a58f18679bbe0e7e50e91)