Improves Support for Positional Only Arguments and Varadic Arguments

[monney]

Motivation

To instantiate objects, or call functions, which require positional only arguments or varadic arguments. Examples include tuple and some numpy functions.

Have you read the [Contributing Guidelines on pull requests]

Yes

Test Plan

I added tests to cover core functionality of the new feature. Some more may be needed.

Related Issues and PRs

Adds support requested in #1432 and #808

[omry]

Thanks @monney.
I will take a closer look in a week or so.

[omry]

Thanks @monney, I am going to take over the PR.
The best way for me to be sure the tests are comprehensive enough is to add the things I think are missing.
I will also update the documentation.

[omry]

Closing in favor of #1470

[monney]

Thanks @omry