Fixes the following compile error:

antsRegistration2DDouble.cxx
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: 'bool ants::VectorPixelCompare<RealType,1>::operator ()(const itk::Vector<TPixel,1> &,const itk::Vector<TPixel,1> &) const': cannot convert argument 1 from 'const _Kty' to 'const itk::Vector<TPixel,1> &' [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: with [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: [ [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: TPixel=RealType [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: ] [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: and [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: [ [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: _Kty=itk::NumericTraits<double>::RealType [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: ] [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: and [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: [ [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: TPixel=RealType [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17): error C2664: ] [C:\Dev\ANTs-VS22\ANTS-build\Examples\antsUtilities.vcxproj]
  (compiling source file '../../../ANTs/Examples/antsRegistration2DDouble.cxx')
  C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17):
  Reason: cannot convert from 'const _Kty' to 'const itk::Vector<TPixel,1>'
          with
          [
              _Kty=itk::NumericTraits<double>::RealType
          ]
          and
          [
              TPixel=RealType
          ]
  C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17):
  Constructor for class 'itk::Vector<TPixel,1>' is declared 'explicit'
          with
          [
              TPixel=RealType
          ]
  C:\Dev\ANTs\Examples\antsUtilities.h(376,3):
  see declaration of 'ants::VectorPixelCompare<RealType,1>::operator ()'
  C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17):
  while trying to match the argument list '(const _Kty, const _Keyty)'
          with
          [
              _Kty=itk::NumericTraits<double>::RealType
          ]
          and
          [
              _Keyty=double
          ]
  C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1610,17):
  the template instantiation context (the oldest one first) is
  	C:\Dev\ANTs\Examples\antsRegistration2DDouble.cxx(10,10):
  	see reference to function template instantiation 'int ants::DoRegistration<double,2>(itk::ants::CommandLineParser::Pointer &)' being compiled
  	C:\Dev\ANTs\Examples\make_interpolator_snip.tmpl(124,1):
  	see reference to class template instantiation 'itk::LabelImageGaussianInterpolateImageFunction<ImageType,RealType,CompareType>' being compiled
  	C:\Dev\ITK-git\Modules\Core\ImageFunction\include\itkLabelImageGaussianInterpolateImageFunction.hxx(41,1):
  	while compiling class template member function 'TOutput itk::LabelImageGaussianInterpolateImageFunction<ImageType,RealType,CompareType>::EvaluateAtContinuousIndex(const itk::ContinuousIndex<TCoordRep,2> &,TOutput *) const'
          with
          [
              TOutput=itk::NumericTraits<double>::RealType,
              TCoordRep=double
          ]
  		C:\Dev\ITK-git\Modules\Core\ImageFunction\include\itkLabelImageGaussianInterpolateImageFunction.h(117,5):
  		see the first reference to 'itk::LabelImageGaussianInterpolateImageFunction<ImageType,RealType,CompareType>::EvaluateAtContinuousIndex' in 'itk::LabelImageGaussianInterpolateImageFunction<ImageType,RealType,CompareType>::EvaluateAtContinuousIndex'
  	C:\Dev\ITK-git\Modules\Core\ImageFunction\include\itkLabelImageGaussianInterpolateImageFunction.hxx(61,17):
  	see reference to class template instantiation 'std::map<TOutput,itk::NumericTraits<double>::RealType,TPixelCompare,std::allocator<std::pair<const TOutput,itk::NumericTraits<double>::RealType>>>' being compiled
          with
          [
              TOutput=itk::NumericTraits<double>::RealType,
              TPixelCompare=CompareType
          ]
  	C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\map(72,20):
  	see reference to class template instantiation 'std::_Tree<std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,false>>' being compiled
          with
          [
              _Kty=itk::NumericTraits<double>::RealType,
              _Ty=itk::NumericTraits<double>::RealType,
              _Pr=CompareType,
              _Alloc=std::allocator<std::pair<const itk::NumericTraits<double>::RealType,itk::NumericTraits<double>::RealType>>
          ]
  	C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1370,25):
  	while compiling class template member function 'std::_Tree_iterator<std::_Tree_val<std::_Tree_simple_types<std::pair<const TOutput,itk::NumericTraits<double>::RealType>>>> std::_Tree<std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,false>>::find(const double &)'
          with
          [
              TOutput=itk::NumericTraits<double>::RealType,
              _Kty=itk::NumericTraits<double>::RealType,
              _Ty=itk::NumericTraits<double>::RealType,
              _Pr=CompareType,
              _Alloc=std::allocator<std::pair<const itk::NumericTraits<double>::RealType,itk::NumericTraits<double>::RealType>>
          ]
  		C:\Dev\ITK-git\Modules\Core\ImageFunction\include\itkLabelImageGaussianInterpolateImageFunction.hxx(74,36):
  		see the first reference to 'std::_Tree<std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,false>>::find' in 'itk::LabelImageGaussianInterpolateImageFunction<ImageType,RealType,CompareType>::EvaluateAtContinuousIndex'
          with
          [
              _Kty=itk::NumericTraits<double>::RealType,
              _Ty=itk::NumericTraits<double>::RealType,
              _Pr=CompareType,
              _Alloc=std::allocator<std::pair<const itk::NumericTraits<double>::RealType,itk::NumericTraits<double>::RealType>>
          ]
  		C:\Dev\ITK-git\Modules\Core\ImageFunction\include\itkLabelImageGaussianInterpolateImageFunction.h(117,5):
  		see the first reference to 'itk::LabelImageGaussianInterpolateImageFunction<ImageType,RealType,CompareType>::EvaluateAtContinuousIndex' in 'itk::LabelImageGaussianInterpolateImageFunction<ImageType,RealType,CompareType>::EvaluateAtContinuousIndex'
  	C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1371,25):
  	see reference to function template instantiation 'std::_Tree_node<std::pair<const TOutput,itk::NumericTraits<double>::RealType>,std::_Default_allocator_traits<_Alloc>::void_pointer> *std::_Tree<std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,false>>::_Find<double>(const _Other &) const' being compiled
          with
          [
              TOutput=itk::NumericTraits<double>::RealType,
              _Alloc=std::allocator<std::pair<const itk::NumericTraits<double>::RealType,itk::NumericTraits<double>::RealType>>,
              _Kty=itk::NumericTraits<double>::RealType,
              _Ty=itk::NumericTraits<double>::RealType,
              _Pr=CompareType,
              _Other=double
          ]
  	C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include\xtree(1361,50):
  	see reference to function template instantiation 'std::_Tree_find_result<std::_Tree_node<std::pair<const TOutput,itk::NumericTraits<double>::RealType>,std::_Default_allocator_traits<_Alloc>::void_pointer> *> std::_Tree<std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,false>>::_Find_lower_bound<_Other>(const _Keyty &) const' being compiled
          with
          [
              TOutput=itk::NumericTraits<double>::RealType,
              _Alloc=std::allocator<std::pair<const itk::NumericTraits<double>::RealType,itk::NumericTraits<double>::RealType>>,
              _Kty=itk::NumericTraits<double>::RealType,
              _Ty=itk::NumericTraits<double>::RealType,
              _Pr=CompareType,
              _Other=double,
              _Keyty=double
          ]

I don't know whether this is the right thing to do.
I was primarily trying to get it to compile.

Message:

C:\Dev\ANTs\Examples\AverageAffineTransform.cxx(314,40): warning C4101: 'e': unreferenced local variable [C:\Dev\ANTs-SB\ANTS-build\Examples\l_AverageAffineTransform.vcxproj]

Example message:

C:\Dev\ANTs\ImageRegistration\itkAvantsMutualInformationRegistrationFunction.cxx(368,54): warning C4834: discarding return value of function with [[nodiscard]] attribute [C:\Dev\ANTs-SB\ANTS-build\Examples\l_ANTS.vcxproj]

Also use the new-style enums.

Ref ANTsX#1652.