COMP: Provide backwards compatible CoordRepType in itk::PolyData

For ITK<5.4.2.

Author: thewtex

include/itkPolyData.h

@@ -58,6 +58,7 @@ class ITK_TEMPLATE_EXPORT PolyData : public DataObject
 
   /** Convenient type alias obtained from TMeshTraits template parameter. */
   using CoordinateType = typename MeshTraits::CoordinateType;
+  using CoordRepType = CoordinateType;
   using PointIdentifier = typename MeshTraits::PointIdentifier;
   using PointType = typename MeshTraits::PointType;
   using PointsContainer = typename MeshTraits::PointsContainer;