anchor.diff:  
   The above query wouldn't highlight "run" or "scissor" but shows that
   it is just fine not to list the field to which the matches are combined
  -(`content`) in the matched fields.
  +(`comment`) in the matched fields.
   
   [NOTE]
   Technically it is also fine to add fields to `matched_fields` that
  
positive.code:     },
      "highlight" : {
          "fields" : {
              "content" : {"type" : "plain"}
          }
      }
  }
  
negative.code: --------------------------------------------------
  {
      "type_name" : {
          "comment" : {"term_vector" : "with_positions_offsets"}
      }
  }
  --------------------------------------------------
  