use the gh- ref instead of bpo- everywhere.

Author: gpshead

Lib/test/test_threading.py

@@ -1173,7 +1173,7 @@ def __del__(self):
 
     @cpython_only
     def test_finalize_daemon_thread_hang(self):
-        # bpo-42969: tests that daemon threads hang during finalization
+        # gh-87135: tests that daemon threads hang during finalization
         script = textwrap.dedent('''
             import os
             import sys

Python/ceval_gil.c

@@ -386,7 +386,7 @@ take_gil(PyThreadState *tstate)
 
     if (_PyThreadState_MustExit(tstate)) {
         /* bpo-36475: If Py_Finalize() has been called and tstate is not
-           the thread which called Py_Finalize(), bpo-42969: hang the
+           the thread which called Py_Finalize(), gh-87135: hang the
            thread.
 
            This code path can be reached by a daemon thread which was waiting