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/freestyle/intern/python/BPy_Interface0D.h

@@ -37,13 +37,13 @@ extern "C" {
 
 extern PyTypeObject Interface0D_Type;
 
-#define BPy_Interface0D_Check(v) (PyObject_IsInstance((PyObject *)v, (PyObject *)&Interface0D_Type))
+#define BPy_Interface0D_Check(v) \
+  (PyObject_IsInstance((PyObject *)v, (PyObject *)&Interface0D_Type))
 
 /*---------------------------Python BPy_Interface0D structure definition----------*/
 typedef struct {
-	PyObject_HEAD
-	Interface0D *if0D;
-	bool borrowed; /* true if *if0D is a borrowed object */
+  PyObject_HEAD Interface0D *if0D;
+  bool borrowed; /* true if *if0D is a borrowed object */
 } BPy_Interface0D;
 
 /*---------------------------Python BPy_Interface0D visible prototypes-----------*/