private static String decodeMissingValue(Tokenizer tokenizer) {
        if (tokenizer.peek() == '"') {
            return tokenizer.dequoteString();
        } else {
            return tokenizer.token();
        }
    }
Creates a new sorting from the given string and returns it, or returns null if the argument does not contain
any sorting criteria (e.g it is null or the empty string)
container-search/src/main/java/com/yahoo/search/query/Sorting.java