add sort function prop

[shrpne]

I'm submitting a ...

• bug report
• feature request
• support request

What is the current behavior?

For now, there is no "official" way to sort suggestions depending on a search query.
I have tried to workaround it by doing sort logic inside list prop function. But using list as non-async function leads to unfixable bug, described in the #301

What is the expected behavior?

I expect to pass a function into sort prop, with parameters like this: sort(a, b, query) {}

What is the motivation / use case for changing the behavior?

I want to sort things :)
For example, I have a list: [Facebook, Faceapp, Facetime, Face]
And I want to move Face in the first position when user inputs Face. I mean exact match moves to the top of the list.
Without such sort and with :max-suggestions=3 user even will not see desired Face in the suggestions at all.