The updated document *
The heads resulting from the change
Note that this is not the same as the heads of newDoc. The newly created
change will be added to the history of newDoc as if it was concurrent
with whatever the heads of the document were at the time of the change.
This means that newHeads will be the same as the heads of a fork of
newDoc at the given heads to which the change was applied.
This field will be null if no change was made
Generated using TypeDoc
The type returned from changeAt