Consider supporting multiline comboboxes

[scottaohara]

Related to https://github.com/w3c/html-aria/issues/543 which was previously logged against aria before i transferred it to the correct spec

Multiline comboboxes, for better or worse, are a thing people are trying to make. Should aria extend the aria-multiline attribute be extended to comboboxes to support such patterns?

One can futz around current guidance by giving a Div a role of combobox and giving it a contenteditable attribute….

And there are comboboxes which don’t allow for full multiline editing, but do visually render as multiline by having values wrap, unlike standard inputs which do not.