Format if statement and add comment

Author: colesbury

Objects/typeobject.c

@@ -6547,10 +6547,14 @@ type_setattro(PyObject *self, PyObject *name, PyObject *value)
     assert(!_PyType_HasFeature(metatype, Py_TPFLAGS_MANAGED_DICT));
 
 #ifdef Py_GIL_DISABLED
+    // gh-139103: Enable deferred refcounting for functions assigned
+    // to type objects.  This is important for `dataclass.__init__`,
+    // which is generated dynamically.
     if (value != NULL &&
         PyFunction_Check(value) &&
-        !_PyObject_HasDeferredRefcount(value)) {
-            PyUnstable_Object_EnableDeferredRefcount(value);
+        !_PyObject_HasDeferredRefcount(value))
+    {
+        PyUnstable_Object_EnableDeferredRefcount(value);
     }
 #endif