[Post-7.0] Improve readability of `Array.from` / `TypedArray.from` `mapFn` parameters

还没有人认领这个 Issue。

Currently, the `mapFn` argument of `Array.from()` is typed as `(v: T, k: number) => U`.
However, when this information is displayed in an IDE tooltip, it is difficult to grasp what values are passed to `v` and `k`.

To improve clarity, I propose changing the type definition to `(element: T, index: number) => U`, following [the description of the same method in MDN Web Docs](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/from). The same applies to TypedArray.from().

Supplementary Information:
- The target file is `internal/bundled/libs/lib.es2015.iterable.d.ts#L107`.
- These changes are not intended to fix differences between 6.0 and 7.0, and according to `CONTRIBUTING.md`, the Pull Request should be submitted after the 7.0 release. I plan to submit a Pull Request for this once 7.0 is released.

从 internal/bundled/libs/lib.es2015.iterable.d.ts#L107 开始，找到 Array.from 和 TypedArray.from 的 mapFn 声明。将它们的参数命名与链接的 MDN 描述进行比较，然后确认这两个声明都使用了描述性的元素名称和索引名称，同时不改变它们的类型或行为。

由索引模型根据 Issue 内容生成。