Out of date documentation, PyCell no longer exists

[KaareH]

I had some trouble using PyCell and got unresolved import 'pyo3::PyCell' despite the latest documentation (0.25.0) mentioning it.

Searching for PyCell (case sensitive), (main branch at the time of writing) revealed that PyCell only appears in documentation and code comments. It appears that legacy documentation has not been removed or updated.

[davidhewitt]

Thanks, yes we kept the PyCell concept around in documentation because we still have runtime borrow checking, however:

• I can agree it's probably confusing and we probably haven't cleaned everything up properly, a pass at cleaning this up would be welcome.
• In the longer term we're heading towards making the borrow-checking opt-in (and having objects immutable by default), which would give us a way to introduce this role concept differently and more elegantly.