[Feature Request] Look into alternative API doc generators

Describe the solution you'd like

We should consider moving away from https://github.com/twisted/pydoctor for Python API docs. It was originally chosen because of how well it handled @overloads. But it doesn't really get updated much and is a bit buggy, e.g. https://python.temporal.io/temporalio.worker.WorkerDeploymentConfig.html is showing those as class variables (because it doesn't understand data classes) and is even missing default_versioning_behavior that is in source with a default.

Open to all options, but I think we want pure API docs generator, not like Sphinx where English docs come along with, but it's worth a try so long as python.temporal.io is pure API docs. Maybe also try https://pdoc.dev/. Or just check around the ecosystem.

Start by reviewing the current pydoctor-generated pages on python.temporal.io, especially WorkerDeploymentConfig, and compare alternative pure Python API documentation generators such as pdoc. Evaluate whether each preserves the requested pure API-docs focus and correctly documents dataclass fields including default_versioning_behavior; done means a documented recommendation or migration path.