Add dedicated Iterator builder for arrays

[daymxn]

Problem

fromItems fails on large arrays, and fromRawParts is too verbose for simple array usage.

Overview

Given an array, there are two ways (afaik) to make an Iterator:

Using fromItems:

Iterator.fromItems(...myArray);

Using fromRawParts:

let i = 0;
Iterator.fromRawParts(
  () => Option.wrap(myArray[i++]),
  fixedSizeHint(myArray.size())
);

fromRawParts is a bit too verbose for simple use cases, and fromItems is the ideal happy path.

Although, fromItems fails on large arrays. When trying to unpack large arrays, you'll get the following error:

too many results to unpack

Proposal

To retain the ideal happy path usage, it would be great if there was a dedicated method for arrays.

public static fromArray<T extends defined>(items: Array<T>): Iterator<T>;

[Dionysusnu]

Does Vec.fromPtr(myArray).iter() provide the behaviour you're after?

On one hand, I generally consider Array<T> to be a non-rust item, so I don't think a built-in conversion for it is necessary. On the other hand, Vec is probably less used than the other rust-classes items, so maybe catering for arrays is worth it.