Add a highlight option to trap the focus on target element

[ranndev]

Is your feature request related to a problem? Please describe.
Currently, we have an autofocus highlight option, but that focus can't easily get away when clicking on other elements around the page. I'm suggesting a new option that can set the focus & trap it to the target element until we removed the highlight.

Describe the solution you'd like
Instead of accepting only boolean value in autofocus highlight option. I'd like to make it also possible to accept 'trap' string value to enable the said feature. And I'd like it to be enabled by default.