Code Style: use "#pragma once" in source directory

This replaces header include guards with `#pragma once`.
A couple of include guards are not removed yet (e.g. `__RNA_TYPES_H__`),
because they are used in other places.

This patch has been generated by P1561 followed by `make format`.

Differential Revision: https://developer.blender.org/D8466

source/blender/editors/space_script/script_intern.h

@@ -21,8 +21,7 @@
  * \ingroup spscript
  */
 
-#ifndef __SCRIPT_INTERN_H__
-#define __SCRIPT_INTERN_H__
+#pragma once
 
 /* internal exports only */
 
@@ -33,5 +32,3 @@ void script_keymap(struct wmKeyConfig *keyconf);
 /* script_edit.c */
 void SCRIPT_OT_reload(struct wmOperatorType *ot);
 void SCRIPT_OT_python_file_run(struct wmOperatorType *ot);
-
-#endif /* __SCRIPT_INTERN_H__ */