Fix classmethod property autodoc (#83) swev-id: sphinx-doc__sphinx-9461

[casey-brooks]

Summary

• document classmethod-backed properties via PropertyDocumenter, preserving abstract metadata
• ensure autosummary selects PropertyDocumenter when classmethod descriptors are exported, including metaclass lookups
• add dedicated autodoc/autosummary fixtures for classmethod properties and cover the autosummary regression reported in Autodoc: document @classmethod@property class-level properties (swev-id: sphinx-doc__sphinx-9461) #83

Resolves #83.

Testing

• PYTHONPATH=/workspace/sphinx pytest tests/test_ext_autodoc_autoproperty.py
• PYTHONPATH=/workspace/sphinx pytest tests/test_ext_autosummary.py::test_autosummary_classmethod_properties
• PYTHONPATH=/workspace/sphinx pytest (fails: 23 pre-existing failures related to typing representation and linkcheck on Python 3.10)

Reproduction notes

• Verified fix with a standalone Sphinx project using .. autoproperty:: demo_pkg.Example.token confirming HTML output includes the classmethod property signature and docstring.
• External demo reproduction (per https://github.com/randolf-scholz/sphinx_demo):
  1. git clone https://github.com/randolf-scholz/sphinx_demo
  2. cd sphinx_demo/docs
  3. make html
  4. open _build/html/dummy_module.submodule.html
• Missing documentation entries before this fix:
  • MetaClass.metaclass_class_property
  • MetaClass.metaclass_abstract_class_property
  • BaseClass.baseclass_class_property
  • BaseClass.baseclass_abstract_class_property
  • SubClass.subclass_class_property
  • SubClass.subclass_abstract_class_property
• Failure mode: no stack trace is emitted; the regression appears as the above entries missing from the generated HTML output.

[casey-brooks]

Test & Lint Summary

• PYTHONPATH=/workspace/sphinx . .venv/bin/activate && pytest tests/test_ext_autodoc_autoproperty.py (6 passed)
• PYTHONPATH=/workspace/sphinx . .venv/bin/activate && pytest tests/test_ext_autosummary.py::test_autosummary_classmethod_properties (1 passed)
• PYTHONPATH=/workspace/sphinx . .venv/bin/activate && pytest tests/test_ext_autosummary.py::test_autosummary_generate_overwrite1 (1 passed)
• PYTHONPATH=/workspace/sphinx . .venv/bin/activate && pytest (1689 passed, 22 skipped, 23 failed — pre-existing typing/linkcheck regressions on Python 3.10)
• . .venv/bin/activate && flake8 sphinx/ext/autodoc/__init__.py sphinx/ext/autosummary/__init__.py tests/test_ext_autodoc_autoproperty.py tests/test_ext_autosummary.py tests/roots/test-ext-autodoc/target/classmethod_properties.py tests/roots/test-ext-autosummary-classmethod (no lint issues)

[noa-lucent]

Looks good to me.