gh-75459: Doc: C API: Improve object life cycle documentation (GH-125962)
* Add "cyclic isolate" to the glossary.
* Add a new "Object Life Cycle" page.
* Improve docs for related API, with special focus on cross-references and warnings
(cherry picked from commit 3246ea514d)
Co-authored-by: Richard Hansen <rhansen@rhansen.org>
Co-authored-by: Petr Viktorin <encukou@gmail.com>
Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
