Implement PyStubType for either::Either (with minor revise)

[termoshtt]

Minor revise for #207

Summary by Copilot

This pull request introduces support for the either crate in the pyo3-stub-gen project, enabling the use of either::Either types in Python stub generation. It also includes minor fixes to existing test cases for improved clarity and correctness.

Integration of the either crate:

• Cargo.toml: Added either as a dependency in the workspace and included it as an optional feature in pyo3-stub-gen. The default features now include either. [1] [2] [3]
• pyo3-stub-gen/src/stub_type.rs: Added a new module either gated behind the either feature flag.
• pyo3-stub-gen/src/stub_type/either.rs: Implemented support for either::Either<L, R> in stub generation by defining type_input and type_output methods that map Either to Python's typing.Union.

Test case fixes:

• pyo3-stub-gen/src/util.rs: Updated test cases to pass string literals directly instead of references, improving readability and correctness.

[Copilot]

Pull Request Overview

This PR implements the PyStubType trait for the either::Either type as part of the minor revisions for issue #207. Key changes include:

• Updating test assertions in util.rs to pass string literals instead of references.
• Adding a new implementation for PyStubType in either.rs.
• Introducing the "either" feature and dependency in Cargo.toml files.

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
pyo3-stub-gen/src/util.rs	Updated test assertions to pass string literals directly.
pyo3-stub-gen/src/stub_type/either.rs	New implementation of PyStubType for either::Either.
pyo3-stub-gen/src/stub_type.rs	Added module inclusion for the new either feature.
pyo3-stub-gen/Cargo.toml	Updated to include the new either dependency and feature in default list.
Cargo.toml	Added the either dependency to the workspace dependencies.