ClangFormat: apply to source, most of intern

Apply clang format as proposed in T53211.

For details on usage and instructions for migrating branches
without conflicts, see:

https://wiki.blender.org/wiki/Tools/ClangFormat

source/blender/python/generic/imbuf_py_api.h

@@ -25,4 +25,4 @@ PyObject *BPyInit_imbuf(void);
 
 extern PyTypeObject Py_ImBuf_Type;
 
-#endif  /* __IMBUF_PY_API_H__ */
+#endif /* __IMBUF_PY_API_H__ */