[Feature Request] Allow __get_item__ calls to use a mix of colon slices and integers

[MadAlex1997]

Review Mojo's priorities

• I have read the roadmap and priorities and I believe this request falls within the priorities.

What is your request?

With the inclusion of Variant it is now possible to write

fn __getitem__(self, owned *slices: Variant[Slice,Int]) raises -> Self:
    pass

But when you call that method using colon slices, like what is used in Python indexes and works for slice only __get_item__, it gives the error "no matching method in call to 'getitem'".

As I believe this is a parser feature, my request is to add the capability to parse a list of mixed inputs of int and slice (specifically colon slices) into something that can be understood by type checking for *slices: Variant[Slice,Int].

What is your motivation for this change?

This will allow more pythonic indexing of multidimensional arrays, and nested objects. Having to manually create slices using Slice is cumbersome.Pythonic

Any other details?

No response