Promotes a specified document to the top level and replaces all other fields.
The operation replaces all existing fields in the input document, including the _id field.
https://docs.mongodb.com/manual/reference/operator/aggregation/replaceRoot
This member is added by an implicit conversion from ReplaceRootField to
any2stringadd[ReplaceRootField] performed by method any2stringadd in scala.Predef.
This member is added by an implicit conversion from ReplaceRootField to
StringFormat[ReplaceRootField] performed by method StringFormat in scala.Predef.
Promotes a specified document to the top level and replaces all other fields. The operation replaces all existing fields in the input document, including the _id field. https://docs.mongodb.com/manual/reference/operator/aggregation/replaceRoot
The field name to become the new root