anchor.diff:  
   The `join` datatype is a special field that creates
   parent/child relation within documents of the same index.
  -This `relations` section defines a set of possible relations within the documents,
  +The `relations` section defines a set of possible relations within the documents,
   each relation being a parent name and a child name.
   A parent/child relation can be defined as follows:
   
  
positive.code: 
  To index a document with a join, the name of the relation and the optional parent
  of the document must be provided in the `source`.
  For instance the following creates a parent document in the `my_parent` context:
  
  [source,js]
  --------------------------------------------------
  
negative.code:   }
  }
  
  PUT my_index/doc/4?routing=1&refresh
  {
    "text": "This is a another child document",
    "my_join_field": {
  