anchor.diff:      "(query|filter)": {},
       "boost": "boost for the whole query",
       "FUNCTION": {},
  -    "boost_mode":"(mult|replace|...)"
  +    "boost_mode":"(multiply|replace|...)"
   }
   --------------------------------------------------
   
  
positive.code: Finally, the newly computed score is combined with the score of the
  query. The parameter `boost_mode` defines how:
  
  `multiply`::    query score and function score is multiplied (default)
  `replace`::     only function score is used, the query score is ignored
  `sum`::         query score and function score are added
  
negative.code:         }
      ],
      "max_boost": number,
      "score_mode": "(multiply|max|...)",
      "boost_mode": "(multiply|replace|...)"
  }
  --------------------------------------------------
  
  