anchor.diff:  if (document.isBlog()) blogEvent.select(new AnnotationLiteral<Updated>(){}).fire(document);
   -------------------------------------------------------------------------------------------
   
  -The above shown event is fired with two qualifiers - `@Blog` and `@Updated`. 
  +The above shown event is fired with two qualifiers - `@Blog` and `@Updated`.
   An observer method is notified if the set of observer qualifiers is a subset of the fired event's qualifiers.
   Assume the following observers in this example:
   
  
positive.code:    }
  }
  -----------------------------------------------------------------------------------
  
negative.code: -----------------------------------------------------------------------------
  
  An observer method need not specify any event qualifiers—in this case it
  is interested in every event whose type is assignable to the observed event type.
  Such observer will trigger on both events shown below:
  
  [source.JAVA, java]
  