DOC: update changelog for &
### Enhancements
+- ``data`` argument is now properly handled by ``Chart.properties`` (#1525)
+
+- Compound charts (layer, concat, hconcat, vconcat) now move data to the top
+ level by default. In particular, this means that the ``facet()`` method
+ can now be called directly on a layered chart without having to change
+ how data is specified. (#1521)
+
- ``alt.LayerChart`` now supports ``mark_*()`` methods. If a layer specifies a
mark at the top level, all child charts will inherit it (unless they override
it explicitly).
