STYLE: use new argList argRead() method and operator[] for cleaner code.

- deprecate argList::additionalArgs() method and remove uses of it

applications/utilities/mesh/advanced/refineWallLayer/refineWallLayer.C

@@ -60,12 +60,10 @@ int main(int argc, char *argv[])
 #   include "createPolyMesh.H"
     const word oldInstance = mesh.pointsInstance();
 
-    word patchName(args.additionalArgs()[0]);
-
-    scalar weight(readScalar(IStringStream(args.additionalArgs()[1])()));
+    const word patchName = args[1];
+    const scalar weight  = args.argRead<scalar>(2);
     const bool overwrite = args.optionFound("overwrite");
 
-
     label patchID = mesh.boundaryMesh().findPatchID(patchName);
 
     if (patchID == -1)