refactor(4DSTARTypes): header guards -> pragma once

src/types/public/4DSTARTypes.h

@@ -18,8 +18,7 @@
 //   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 //
 // *********************************************************************** */
-#ifndef _4DSTAR_TYPES_H
-#define _4DSTAR_TYPES_H
+#pragma once
 
 #include <utility>
 #include "mfem.hpp"
@@ -29,5 +28,3 @@ namespace SSE {
     typedef std::pair<mfem::Array<int>, mfem::Array<double>> MFEMArrayPair;
     typedef std::pair<MFEMArrayPair, MFEMArrayPair> MFEMArrayPairSet;
 }
-
-#endif // _4DSTAR_TYPES_H