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/miscellaneous/patchSummary/patchSummaryTemplates.C

@@ -39,7 +39,7 @@ void Foam::addToFieldList
     const typename GeoField::Mesh& mesh
 )
 {
-    if (obj.headerClassName() == GeoField::typeName)
+    if (obj.isHeaderClass<GeoField>())
     {
         fieldList.set
         (