[3.13] gh-93096: Fix loading doctests in test_pickle (GH-131069) (GH-131080)

(cherry picked from commit 3bb20d1)

Co-authored-by: donBarbos <[email protected]>

Author: miss-islington

Lib/test/test_pickle.py

@@ -700,7 +700,7 @@ def test_multiprocessing_exceptions(self):
 
 
 def load_tests(loader, tests, pattern):
-    tests.addTest(doctest.DocTestSuite())
+    tests.addTest(doctest.DocTestSuite(pickle))
     return tests