Update docs on "highlightOnTouch"
Update docs on "highlightOnTouch"

Clarify that enabling `highlightOnTouch` will still propagate the touch
event to the parent widget.

Change-Id: Ida1c7aa3a75440c413e901d5b98295df11de09a9

eclipsesource/tabris-js,eclipsesource/tabris-js,eclipsesource/tabris-js