anchor.diff:  // CONSOLE
   // TEST[continued]
   
  -<1> This child document must be on the same shard than its parent
  +<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
   
  
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 two parent documents in the `question` context:
  
  [source,js]
  --------------------------------------------------
  
negative.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 example shows how to index two `child` documents:
  
  [source,js]
  --------------------------------------------------
  