Add changelog

Documentation/release/dev/improve-amr-selection-support.md

@@ -4,4 +4,9 @@ vtkExtractSelection now properly works for vtkUniformGridAMR subclasses.
 This was achieved by Modifying vtkDataObjectTree to support vtkUniformGridAMR for CopyStructure, GetDataSet, SetDataSet.
 Also when creating the hierarchy of a vtkUniformGrid, now all composite indices are in a level are included.
 Finally, as we prepare to deprecate vtkMultiBlockDataSet, if the input is a vtkUniformGridAMR, vtkExtractSelection now
-generates a vtkPartitionedDataSetCollection instead of a vtkMultiBlockDataSet.
+generates a vtkPartitionedDataSetCollection instead of a vtkMultiBlockDataSet. Also the following protected function
+has been deprecated.
+```
+void CutAMRBlock(
+vtkPlane* cutPlane, unsigned int blockIdx, vtkUniformGrid* grid, vtkMultiBlockDataSet* dataSet);
+```