@Override
        public void visit(Choice choice) {
            if (choice.alternatives().size()<2) return; // No choice...
            resolve(choice,query,result,resolution);
        }
Override this to resolve <i>each</i> map choice independently.
This default implementation does nothing.

@param choice the choice to resolve
@param query the query for which this should be resolved, typically used to extract features
@param result the result for which this should be resolved, typically used to extract features
@param resolution the set of resolutions made so far, to which this should be added:
       <code>resolution.addMapChoiceResolution(choice,chosenMapping)</code>
container-search/src/main/java/com/yahoo/search/pagetemplates/engine/Resolver.java