code: private static Element incrementContentScore(Element node, int increment) {
          int contentScore = getContentScore(node);
          contentScore += increment;
          node.attr(CONTENT_SCORE, Integer.toString(contentScore));
          return node;
      }
docs: Increase or decrease the content score for an Element by an
  increment/decrement.
  
  @param node
  @param increment
  @return