ENH: allow modifiable access to IOobject local(), as per instance()

ENH: simplify code by using fieldTypes::is_xxx() tests

applications/utilities/postProcessing/dataConversion/foamToEnsight/checkFieldAvailability.H

@@ -57,14 +57,7 @@ forAll(meshes, regioni)
         if (!doPointValues)
         {
             // Prune point fields if disabled
-            objects.filterClasses
-            (
-                [](const word& clsName)
-                {
-                    return fieldTypes::point.found(clsName);
-                },
-                true // prune
-            );
+            objects.filterClasses(Foam::fieldTypes::is_point, true);
         }
     }