Downshift: onUserAction typings issue

[srishanbhattarai]

• downshift version: 1.22.1
• node version: 8.9.10
• npm (or yarn) version: yarn 0.27.5

What you did:
Tried following the autosuggest example in TypeScript.

What happened:
Could not use the type property on onUserAction's callback parameter - as seen here.

Problem description:
The typings for onUserAction options do not contain the type string which leads to the usual
Property 'type' does not exist on type 'StateChangeOptions' error.

Suggested solution:
The typings need to be updated. Also, it seems that the onUserAction callback is not documented. I can open a PR with these fixes.

EDIT: Just realized its plainly stated that this wont be documented.

[kentcdodds]

I'd be willing to accept a pull request to update the TypeScript definitions. I'm warming up to the "experimental feature" anyway :)

[tansongyang]

If no one's taking this, I've got time to work on it.

[tansongyang]

Closing because this has already been merged.