not-wp
Negate a waypoint marker — visible on all subslides except the referenced ones.
Works with bare labels, from-wp, until-wp, prev-wp, next-wp,
get-first, get-last, or any other waypoint marker.
Like the "!" prefix for strings, not-wp cannot introduce new subslides —
it only masks existing ones.
Example: #only(not-wp(<my-label>))[hidden during my-label]
Parameters
wp : label | dictionary
A waypoint label or marker to negate.
Returns: dictionary