code: public Elements getElementsByAttributeValueContaining(String key, String match) {
          return Collector.collect(new Evaluator.AttributeWithValueContaining(key, match), this);
      }
docs: Find elements that have attributes whose value contains the match string. Case insensitive.
  
  @param key name of the attribute
  @param match substring of value to search for
  @return elements that have attributes containing this text