Style: Replace header guards with #pragma once

scene/3d/node_3d.h

@@ -28,8 +28,7 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
 /**************************************************************************/
 
-#ifndef NODE_3D_H
-#define NODE_3D_H
+#pragma once
 
 #include "scene/main/node.h"
 #include "scene/resources/3d/world_3d.h"
@@ -305,5 +304,3 @@ public:
 };
 
 VARIANT_ENUM_CAST(Node3D::RotationEditMode)
-
-#endif // NODE_3D_H