Observe Some (Generic) Publisher

[albertbori]

Description

This PR introduces a small change which allows the observation of some Publisher<Value, Failure> instead of explicitly requiring AnyPublisher<Value, Failure>. This helps reduce the amount of typing when building view state models.

Previous:

struct LoaderModel {
    func load() -> AnyPublisher<MyViewState, Never> {
        Just(.loading)
            .merge(with: webRequestPublisher())
            .eraseToAnyPublisher()
    }
}

Current as of this PR:

struct LoaderModel {
    func load() -> some Publisher<MyViewState, Never> {
        Just(.loading)
            .merge(with: loadPublisher())
    }
}

Prior to this PR, the above code would cause an error if you tried to observe that function like so:

$state.observe(loaderModel.load())

Type of Change

• [ ] Bug Fix
• [x] New Feature
• [ ] Breaking Change
• [ ] Refactor
• [ ] Documentation
• [ ] Other (please describe)

Checklist

• [x] I have read the contributing guidelines
• [x] Existing issues have been referenced (where applicable)
• [x] I have verified this change is not present in other open pull requests
• [x] Functionality is documented
• [x] All code style checks pass
• [x] New code contribution is covered by automated tests
• [x] All new and existing tests pass