Auto merge of #111278 - EFanZh:implement-from-array-refs-for-vec, r=dtolnay

Implement `From<{&,&mut} [T; N]>` for `Vec<T>` where `T: Clone`

Currently, if `T` implements `Clone`, we can create a `Vec<T>` from an `&[T]` or an `&mut [T]`, can we also support creating a `Vec<T>` from an `&[T; N]` or an `&mut [T; N]`? Also, do I need to add `#[inline]` to the implementation?

ACP: rust-lang/libs-team#220. [Accepted]

Closes #100880.

Author: bors