[docs] [issue26515] Update extending/embedding docs to new way to build modules in C

Petr Viktorin <encukou@gmail.com> added the comment: Correct usage of multi-phase init might now get users stuck when they start needing per-module state. See PEP 573 "Module State Access from C Extension Methods" for the (hopefully) last thing that prevents me from generally recommending multi-phase init. That PEP is on my list for after PRP 590 is done. Before it's implemented, I'm happy leaving PyModuleDef_Init to experts -- that is, have it in the reference docs only. ---------- _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue26515> _______________________________________