[VTK-4471] Fix script injecition vulnerability
[VTK-4471] Fix script injecition vulnerability

No longer treat 'description' as 'introduction' in listings, since
'description' has no restrictions on the HTML content, and it is being
output without HTML-escaping in listings.

vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk