Filters/ParallelDIY2: install `vtkDIYKdTreeUtilities`

Used within ParaView.

Documentation/release/dev/missing-headers.md

@@ -4,3 +4,4 @@ Headers that were treated as private but should have been public are now
 installed.
 
 - `vtkBlockSortHelper.h` from `VTK::RenderingVolume`
+- `vtkDIYKdTreeUtilities.h` from `VTK::FiltersParallelDIY2`

Filters/ParallelDIY2/CMakeLists.txt

@@ -7,6 +7,7 @@ vtk_object_factory_declare(
 
 set(classes
   vtkAdaptiveResampleToImage
+  vtkDIYKdTreeUtilities
   vtkExtractSubsetWithSeed
   vtkGenerateGlobalIds
   vtkGhostCellsGenerator
@@ -33,6 +34,6 @@ vtk_object_factory_configure(
 
 vtk_module_add_module(VTK::FiltersParallelDIY2
   CLASSES ${classes}
-  SOURCES ${vtk_object_factory_source} vtkDIYKdTreeUtilities.cxx
-  PRIVATE_HEADERS ${vtk_object_factory_header} vtkDIYKdTreeUtilities.h)
+  SOURCES ${vtk_object_factory_source}
+  PRIVATE_HEADERS ${vtk_object_factory_header})
 vtk_add_test_mangling(VTK::FiltersParallelDIY2)