Support functions for callable protocols and typing aliases, plus a talks and articles page

[mauvilsa]

What does this PR do?

Improvements to protocol and Callable type support, fixes for unsubscripted typing aliases, and documentation restructuring.

Added

• A protocol whose single method is __call__ is now also implemented by a function with a compatible signature, so the import path of a function is accepted as value. The value is then the function itself, instead of a class to instantiate. --*.help for such a value gives a clear error, since a function has no class to describe.

Fixes #616

Fixed

• Functions without a return annotation at runtime, e.g. C-implemented ones like time.localtime, were rejected for Callable types with a class return type. Now the return type from a .pyi is used when the stubs resolver is enabled.
• Unsubscripted typing sequence aliases (List, Sequence, MutableSequence, Iterable, Collection, Container, Reversible and Deque) raised AttributeError: __args__, which made classes that have one in their signature, e.g. torch.utils.data.DataLoader, impossible to add.
• typing.Hashable and typing.Sized were not supported, while the collections.abc spelling of the same types was. A bare one didn't validate and a composed one, e.g. Optional[Hashable], raised Unsupported type hint.

Documentation

• New orphan page talks-and-articles collecting presentations, videos, blog posts and example projects, replacing the shorter Tutorials section in DOCUMENTATION.rst. Linked from the README and from CONTRIBUTING.rst.
• The Comparison to Fire section moved into the auto_cli docstring, where it is more discoverable.
• CONTRIBUTING.rst rephrased for conciseness.
• Documented the new function-implements-protocol behavior and the return type requirement for functions given to Callable types.

Before submitting

• Did you read the contributing guideline?
• If you used a coding agent, did you fully understand and validate all generated code and ensure it follows the contributing guidelines?
• Did you update the documentation? (readme and public docstrings)
• Did you write unit tests such that there is 100% coverage on related code? (required for bug fixes and new features)
• Did you verify that new and existing tests pass locally?
• If this is a bug fix, did you verify that the tests fail without the code fix?
• Did you make sure that all changes preserve backward compatibility?
• Did you update the CHANGELOG including a pull request link? (not for typos, docs, test updates, or minor internal changes/refactors)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (72c4885) to head (0baffc5).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #963   +/-   ##
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  Coverage   100.00%   100.00%           
=========================================
  Files           28        28           
  Lines         9162      9209   +47     
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+ Hits          9162      9209   +47     

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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