anchor.diff:  ==== Multi Field
   
   The `query_string` query can also run against multiple fields. Fields can be
  -provided via the `"fields"` parameter (example below).
  +provided via the `fields` parameter (example below).
   
   The idea of running the `query_string` query against multiple fields is to
   expand each query term to an OR clause like this:
  
positive.code: 
  The `query_string` query supports multi-terms synonym expansion with the <<analysis-synonym-graph-tokenfilter,
  synonym_graph>> token filter. When this filter is used, the parser creates a phrase query for each multi-terms synonyms.
  For example, the following synonym: `"ny, new york" would produce:`
  
  `(ny OR ("new york"))`
  
  
negative.code:     "query": {
          "query_string" : {
              "default_field" : "content",
              "query" : "(new york city) OR (big apple)" <1>
          }
      }
  }
  --------------------------------------------------
  // CONSOLE
  
  <1> will be split into `new york city` and `big apple` and each part is then
  analyzed independently by the analyzer configured for the field.
  
  WARNING: Whitespaces are not considered operators, this means that `new york city`
  