Change keyboard level include guards to pragma once (#14248)

* Change keyboard level include guards to `pragma once`

And clean up a lot of layout macros

* Oops

* Remove dangling endif

keyboards/clueboard/60/60.h

@@ -13,9 +13,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-#ifndef CLUEBOARD60_H
-#define CLUEBOARD60_H
+
+#pragma once
 
 #include "quantum.h"
-
-#endif