anchor.diff:                    },
                     "_score": 1.0444683,
                     "fields": {
  -                    "comments.text": [
  +                    "comments.text.keyword": [
                         "words words words"
                       ]
                     }
  
positive.code: the relevant bit for the nested document is included as source in the inner hit. Doing this for each matching nested document
  has an impact on the time it takes to execute the entire search request, especially when `size` and the inner hits' `size`
  are set higher than the default. To avoid the relatively expensive source extraction for nested inner hits, one can disable
  including the source and solely rely on stored fields. Like this:
  
  [source,js]
  --------------------------------------------------
  
negative.code:     "doc": {
        "properties": {
          "comments": {
            "type": "nested"
          }
        }
      }
  