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/plugins/cpptools/baseeditordocumentprocessor.h

@@ -23,8 +23,7 @@
 **
 ****************************************************************************/
 
-#ifndef BASEEDITORDOCUMENTPROCESSOR_H
-#define BASEEDITORDOCUMENTPROCESSOR_H
+#pragma once
 
 #include "baseeditordocumentparser.h"
 #include "cppsemanticinfo.h"
@@ -99,6 +98,3 @@ private:
 };
 
 } // namespace CppTools
-
-#endif // BASEEDITORDOCUMENTPROCESSOR_H
-