fix negation bubbling for specific occurrences for AND NOT only paths

Is this equivalent to ``code != 'DENEXCEP'`` OR ``!result.get('NUMER')`` OR ``result.get(code)`` (by simplifying the negation)?

Is the intent to avoid showing the rationale if the ``code`` is DENEXCEP and there is a ``result`` value for NUMER and no ``result`` value for DENEXCEP?