[combobox][select] List header with "Select all visible"

# Feature request

## Summary

I'd like to request support for a built-in way to render a "Select all visible" option so selecting mutlitple options can be done with 1 click on top pinned item in Combobox list.
My suggestion is to add new components - ListHeader and SelectAll so usage may look like this:
```tsx

{(item) => (

{item.label}

)}

```

## Examples in other libraries

[Prime React](https://primereact.org/multiselect/)

## Motivation

I'm trying to create a combobox with top pinned option that changes selection for all visible options.

I was able to achive that behaviour with controlled api and some additional context, but I think it would be nice to have same functionality out of the box and for uncontrolled component as well.