STYLE: remove old references to 'dx' and 'foamFile'

etc/controlDict

@@ -498,7 +498,6 @@ DebugSwitches
     flowRateInletVelocity   0;
     fluxCorrectedVelocity   0;
     foamChemistryReader 0;
-    foamFile            0;
     forceCoeffs         0;
     forces              0;
     fourth              0;

tutorials/combustion/reactingFoam/RAS/SandiaD_LTS/system/sampleDict

@@ -26,8 +26,7 @@ setFormat raw;
 
 // Surface output format. Choice of
 //      null        : suppress output
-//      foamFile    : separate points, faces and values file
-//      dx          : DX scalar or vector format
+//      foam        : separate points, faces and values file
 //      vtk         : VTK ascii format
 //      raw         : x y z value format for use with e.g. gnuplot 'splot'.
 //