`autodoc_mock_imports` mock's type hint fails for `|` operator

[mtsokol]

Describe the bug

Modules mocked with autodoc_mock_imports don't support | for type hinting, when used as e.g. type hints in function's parameters.

How to Reproduce

# conf.py
autodoc_mock_imports = [ 'mock_module' ]

# somewhere in the API
def func_to_autodoc(
  myclass1: Optional[mock_module.MyClass] = None,  # OK
  myclass2: mock_module.MyClass | None = None,  # Fails with | not supported
): ...

Environment Information

Platform:              darwin; (macOS-26.2-arm64-arm-64bit)
Python version:        3.11.14 | packaged by conda-forge | (main, Oct 22 2025, 22:56:31) [Clang 19.1.7 ])
Python implementation: CPython
Sphinx version:        8.2.3
Docutils version:      0.21.2
Jinja2 version:        3.1.6
Pygments version:      2.19.2

Sphinx extensions

extensions = [
    'sphinx.ext.autodoc',
]

Additional context

No response

[Mr-Neutr0n]

Opened a PR for this: #14303