Implement the Compobox

[t1m4lc]

It's probably like the listbox but with autocomplete behaviour.

https://headlessui.dev/react/combobox

[multiplehats]

Only thing that requires this is to merge this PR: #126

Seems like it's good to go.

[ryou90]

HI folks,
there is already a implementation https://github.com/NoelOConnell/svelte-headlessui/tree/combobox-component
You can also find the package on https://www.npmjs.com/package/svelte-headlessui-combobox-temporary

There exists also a really new kind of implementation here: https://github.com/CaptainCodeman/svelte-headlessui