Style: Replace header guards with #pragma once

core/variant/variant_internal.h

@@ -28,8 +28,7 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
 /**************************************************************************/
 
-#ifndef VARIANT_INTERNAL_H
-#define VARIANT_INTERNAL_H
+#pragma once
 
 #include "variant.h"
 
@@ -1590,5 +1589,3 @@ struct VariantTypeConstructor {
 		memnew_placement(r_value, T(*reinterpret_cast<Variant *>(p_variant)));
 	}
 };
-
-#endif // VARIANT_INTERNAL_H