anchor.diff:  
   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 two parent documents in the `question` context:
  +For instance the following example creates two `parent` documents in the `question` context:
   
   [source,js]
   --------------------------------------------------
  
positive.code: WARNING: It is required to index the lineage of a parent in the same shard so you must
  always route child documents using their greater parent id.
  
  For instance the following index two children documents pointing to the same parent `1`
  with a `routing` value equals to the `id` of the parent:
  
  [source,js]
  --------------------------------------------------
  
negative.code: // CONSOLE
  // TEST[continued]
  
  <1> The routing value is mandatory because parent and child documents must be indexed on the same shard
  <2> `answer` is the name of the join for this document
  <3> The parent id of this child document
  
  