Cleanup: PyMethodDef formatting

Missed these changes in [0].

Also replace designated initializers in some C code, as it's not used
often and would need to be removed when converting to C++.

[0] e555ede626

source/blender/python/gpu/gpu_py_api.c

@@ -32,8 +32,14 @@ PyDoc_STRVAR(pygpu_doc,
              "Some higher level functions can be found in the `gpu_extras` module.");
 static struct PyModuleDef pygpu_module_def = {
     PyModuleDef_HEAD_INIT,
-    .m_name = "gpu",
-    .m_doc = pygpu_doc,
+    /*m_name*/ "gpu",
+    /*m_doc*/ pygpu_doc,
+    /*m_size*/ 0,
+    /*m_methods*/ NULL,
+    /*m_slots*/ NULL,
+    /*m_traverse*/ NULL,
+    /*m_clear*/ NULL,
+    /*m_free*/ NULL,
 };
 
 PyObject *BPyInit_gpu(void)