bpo-31095: Fix potential crash during GC (GH-3197)

(cherry picked from commit a6296d34a478b4f697ea9db798146195075d496c)
diff --git a/Doc/includes/noddy4.c b/Doc/includes/noddy4.c
index 9feb71a..0fd4dc3 100644
--- a/Doc/includes/noddy4.c
+++ b/Doc/includes/noddy4.c
@@ -46,6 +46,7 @@
 static void
 Noddy_dealloc(Noddy* self)
 {
+    PyObject_GC_UnTrack(self);
     Noddy_clear(self);
     Py_TYPE(self)->tp_free((PyObject*)self);
 }