STYLE: prefer isHeaderClass<Type>() check instead of Type::typeName

- use typeHeaderOk<regIOobject>(false) for some generic file existence
  checks. Often had something like labelIOField as a placeholder, but
  that may be construed to have a particular something.

applications/utilities/postProcessing/lumped/lumpedPointForces/lumpedPointForces.C

@@ -52,9 +52,9 @@ autoPtr<GeoFieldType> loadField
     const IOobject* io
 )
 {
-    if (io && io->headerClassName() == GeoFieldType::typeName)
+    if (io && io->isHeaderClass<GeoFieldType>())
     {
-        Info<< "Reading " << GeoFieldType::typeName
+        Info<< "Reading " << io->headerClassName()
             << ' ' << io->name() << endl;
 
         return autoPtr<GeoFieldType>::New