ENH: Added dixygen tags to function objects

src/postProcessing/functionObjects/utilities/CourantNo/CourantNo.H

@@ -24,6 +24,9 @@ License
 Class
     Foam::CourantNo
 
+Group
+    grpUtilitiesFunctionObjects
+
 Description
     This function object calculates and outputs the Courant number as a
     volScalarField.  The field is stored on the mesh database so that it can

src/postProcessing/functionObjects/utilities/scalarTransport/scalarTransport.H

@@ -24,6 +24,9 @@ License
 Class
     Foam::scalarTransport
 
+Group
+    grpUtilitiesFunctionObjects
+
 Description
     This function object evolves a passive scalar transport equation.  The
     field in ininitially zero, to which sources are added.  The field name