Fix doc
The iteration can stop if the `Done()` method returns true, not false.
@@ -106,7 +106,7 @@ type MapIterator interface {
Next() (key Node, value Node, err error)
// Done returns false as long as there's at least one more entry to iterate.
- // When Done returns false, iteration can stop.
+ // When Done returns true, iteration can stop.
//
// Implementers of iterators for advanced data layouts (e.g. more than
// one chunk of backing data, which is loaded incrementally), if your
