static String nearAnnotations(NearItem n) {
            if (n.getDistance() != NearItem.defaultDistance) {
                return "{" + DISTANCE + ": " + n.getDistance() + "}";
            } else {
                return "";
            }
        }
Serialize Vespa query trees to YQL+ strings.

@author Steinar Knutsen
container-search/src/main/java/com/yahoo/search/yql/VespaSerializer.java