Wholesale conversion to #pragma once

Kudos to cgmb and https://github.com/cgmb/guardonce

Change-Id: Ifa8970734b8d43fd08c9260c645bdb0228633791
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>

src/libs/utils/utilsicons.h

@@ -23,8 +23,7 @@
 **
 ****************************************************************************/
 
-#ifndef UTILSICONS_H
-#define UTILSICONS_H
+#pragma once
 
 #include "icon.h"
 
@@ -36,5 +35,3 @@ const Utils::Icon EDIT_CLEAR({
 
 } // namespace Icons
 } // namespace Utils
-
-#endif // UTILSICONS_H