STYLE: use range-for when looping dictionary entries.

- as part of the cleanup of dictionary access methods (c6520033c9)
  made the dictionary class single inheritance from IDLList<entry>.

  This eliminates any ambiguities for iterators and allows
  for simple use of range-for looping.

  Eg,
      for (const entry& e : topDict))
      {
          Info<< "entry:" << e.keyword() << " is dict:" << e.isDict() << nl;
      }

   vs

      forAllConstIter(dictionary, topDict, iter))
      {
          Info<< "entry:" << iter().keyword()
              << " is dict:" << iter().isDict() << nl;
      }

src/sampling/sampledSurface/writers/ensight/ensightSurfaceWriterTemplates.C

@@ -346,14 +346,15 @@ Foam::fileName Foam::ensightSurfaceWriter::writeCollated
                 << "VARIABLE" << nl;
 
             const dictionary& fieldsDict = dict.subDict("fields");
-            forAllConstIter(dictionary, fieldsDict, iter)
+            for (const entry& dEntry : fieldsDict)
             {
-                const dictionary& subDict = iter().dict();
+                const dictionary& subDict = dEntry.dict();
+
                 const word fieldType(subDict.get<word>("type"));
                 const word varName = subDict.lookupOrDefault
                 (
                     "name",
-                    iter().keyword() // fieldName as fallback
+                    dEntry.keyword() // fieldName as fallback
                 );
 
                 osCase