Allow `Waker::from` to accept trait object `Arc<dyn Wake>`

I don't know it this issue is duplicate.

Consider this code snippet

use std::{sync::Arc, task::{Wake, Waker}};

trait Foo: Send + Sync {}
impl Wake for dyn Foo {
    fn wake(self: Arc<Self>) {
        todo!()
    }
}

struct Object;
impl Foo for Object {}

fn main() {
    let foo = Arc::new(Object) as Arc<dyn Foo>;
    Waker::from(foo);
}

Currently this code doesn't work, Because Waker::from cannot be used with Arc<dyn Wake>

https://github.com/rust-lang/rust/blob/1e4f10ba6476e48a42a79b9f846a2d9366525b9e/library/alloc/src/task.rs#L109

It would be ideal if Waker::from could support W: ?Sized objects by relaxing the Sized bound on W.

Open library/alloc/src/task.rs at the linked Waker::from implementation and reproduce the provided Rust snippet on stable to confirm the current failure. Trace the conversion's bounds and update it so Arc is accepted; done when the snippet compiles and existing standard-library checks remain passing.