STYLE: Replace itkStaticConstMacro with static constexpr

Use static constexpr directly now that C++11 conformance
is required by all compilers.

:%s/itkStaticConstMacro *( *\([^,]*\),[ \_s]*\([^,]*\),\_s*\([^)]*\)) */static constexpr \2 \1 = \3/ge

'itkStaticConstMacro(name, type, value)' became unconditionally
identical to 'static constexpr type name = value' with ITK commit
aec95193ab00e1322039911e1032da00f3a103b6 "ENH: Update compiler macros (#810)",
maekclena, 7 May 2019.

'itkGetStaticConstMacro(name)' became unconditionally identical to
'(Self::name)' with ITK commit 84e490b81e3f3c2b0edb89ae7b9de53bfc52f2b2
"Removing some outdated compiler conditionals", Hans Johnson, 31 July
2010.

Most 'itkStaticConstMacro' calls were removed by ITK commit 5c14741e1e063a132ea7e7ee69c5bd0a4e49af74

Author: hjmjohnson

include/itkImageToPointSetFilter.h

@@ -71,10 +71,10 @@ class ITK_TEMPLATE_EXPORT ImageToPointSetFilter: public ImageToMeshFilter< TInpu
   using PointDataContainerIterator = typename PointDataContainer::Iterator;
 
   /** The dimension of the output mesh. */
-  itkStaticConstMacro(PointDimension, unsigned int, TOutputMesh::PointDimension);
+  static constexpr unsigned int PointDimension = TOutputMesh::PointDimension;
 
   /** ImageDimension constant */
-  itkStaticConstMacro(ImageDimension, unsigned int, TInputImage::ImageDimension);
+  static constexpr unsigned int ImageDimension = TInputImage::ImageDimension;
 
 protected:
   ImageToPointSetFilter() {}