Documentation: update that semanticdiff outputs to stdout
Documentation: update that semanticdiff outputs to stdout

keithroe/vtkoptix,keithroe/vtkoptix,SimVascular/VTK,sumedhasingla/VTK,keithroe/vtkoptix,sumedhasingla/VTK,SimVascular/VTK,SimVascular/VTK,keithroe/vtkoptix,SimVascular/VTK,sumedhasingla/VTK,sumedhasingla/VTK,SimVascular/VTK,keithroe/vtkoptix,sumedhasingla/VTK,keithroe/vtkoptix,sumedhasingla/VTK,sumedhasingla/VTK,sumedhasingla/VTK,SimVascular/VTK,keithroe/vtkoptix,SimVascular/VTK,keithroe/vtkoptix,SimVascular/VTK