Allow to disable aut-highlight of the choice item in drop-down

[Fedik]

Is your feature request related to a problem? Please describe.

Currently when doing search choices.js will aut-highlight a first item in drop-down list.

This sometimes is undesired behavior, example when I have extra JS that handle Enter keydown to add a custom Choice item (For tagging feature when (with select-multiple) I have tag Green Lemon, and want to add new Green then choices.js will highlight Green Lemon and that not allow to add Green on Enter)

Describe the solution you'd like Maybe a little option autoHighlight:false that prevent call this._highlightChoice(); when it not "mouseover" or "key navigation"

Thanks.