bpo-26868: Fix example usage of PyModule_AddObject. (GH-15725)


* Add a note to the PyModule_AddObject docs.

* Correct example usages of PyModule_AddObject.

* Whitespace.

* Clean up wording.

* 📜🤖 Added by blurb_it.

* First code review.

* Add < 0 in the tests with PyModule_AddObject
(cherry picked from commit 224b8aaa7e8f67f748e8b7b6a4a77a25f6554651)

Co-authored-by: Brandt Bucher <brandtbucher@gmail.com>
9 files changed