how to accomplish `zip_mut_with` in faster?

hey,

I have spent a few minutes trying unsuccessfully to write a simd version of code that uses ndarray's [`zip_mut_with`](https://docs.rs/ndarray/0.10.14/ndarray/struct.ArrayBase.html#method.zip_mut_with) - is there currently a way of combining a `simd_iter_mut` and `simd_iter` with `zip`?

Essentially, I'd like to modify the elements of an array in place with an operation that uses the values in another array of the same shape.

I tried this:

```rust
let mut xs = ndarray::Array::from_elem((64,), 0.0f32);
let ys = ndarray::Array::from_elem((64,), 1.0f32);
(xs.as_slice_mut().unwrap().simd_iter_mut(f32s(0.0)),
ys.as_slice().unwrap().simd_iter(f32s(0.0)))
.zip()
.simd_for_each(|(x, y)| {
*x += *y; // or whatever, not sure if this is correct for the closure
});
```

and got this error:

```console
error[E0599]: no method named `simd_for_each` found for type `faster::Zip<(faster::SIMDIter<&mut [f32]>, faster::SIMDIter<&[f32]>)>` in the current scope
--> src/mlp/m3r.rs:298:26
|
298 | .simd_for_each(|(z, b)| {
| ^^^^^^^^^^^^^
...
```

Any recommendations for how to proceed? First time using the library, apologies if this is an obvious question.