Quality of Life: Using ParamSpec to show underlying typehinting

[JackUrb]

Why are the changes needed?

Generally using flyte's task and workflow decorators leads to having slightly less ability to introspect on the wrapped functions after-the-fact from within an IDE like VSCode. The lost documentation makes quickly reasoning through functions difficult without having to directly click through to the original source.

For flyte users, it would be best to have the workflow and task function's wrapping function return the wrapped signature first, and then the generic.

What changes were proposed in this pull request?

• Introduces using ParamSpec to retain the parameterization typing of the callable's inputs
• Changes the order of the returned Union type to prefer the user's function specification.

How was this patch tested?

Running tests locally.

Checking typing of some of the functions I used in the tests of #2614 to see the information locally.

Screenshots

Before:
@workflow

@task

After:
@workflow

@task

@dynamic

Check all the applicable boxes

• I updated the documentation accordingly.
• All new and existing tests passed.
• All commits are signed-off.

[eapolinario]

Thank you!

Even though this doesn't bring full support for mypy yet (we plan to invest in this WIP PR), it's a step in the right direction. Let's get this in so that at least IDEs can start having a better time with flytekit type hints.

[welcome]

Congrats on merging your first pull request! 🎉