[3.14] gh-136549: Fix signature of threading.excepthook() (GH-136559) (GH-136589)

(cherry picked from commit be2c3d284e)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Lib/test/test_inspect/test_inspect.py

@@ -5916,6 +5916,7 @@ def test_sysconfig_module_has_signatures(self):
     def test_threading_module_has_signatures(self):
         import threading
         self._test_module_has_signatures(threading)
+        self.assertIsNotNone(inspect.signature(threading.__excepthook__))
 
     def test_thread_module_has_signatures(self):
         import _thread

Misc/NEWS.d/next/Library/2025-07-11-23-04-39.gh-issue-136549.oAi8u4.rst

@@ -0,0 +1 @@
+Fix signature of :func:`threading.excepthook`.

Modules/_threadmodule.c

@@ -2317,7 +2317,7 @@ thread_excepthook(PyObject *module, PyObject *args)
 }
 
 PyDoc_STRVAR(excepthook_doc,
-"_excepthook($module, (exc_type, exc_value, exc_traceback, thread), /)\n\
+"_excepthook($module, args, /)\n\
 --\n\
 \n\
 Handle uncaught Thread.run() exception.");