Disambiguate issue reference

Co-authored-by: Peter Bierma <[email protected]>

Author: johnslavik

Lib/test/test_pyrepl/test_pyrepl.py

@@ -1407,7 +1407,7 @@ def test_dumb_terminal_exits_cleanly(self):
         env = os.environ.copy()
         env.pop('PYTHON_BASIC_REPL', None)
         # Ignore PYTHONSTARTUP to not pollute the output
-        # with an unrelated traceback. See #137568
+        # with an unrelated traceback. See GH-137568.
         env.pop('PYTHONSTARTUP', None)
         env.update({"TERM": "dumb"})
         output, exit_code = self.run_repl("exit()\n", env=env)