Provide a little better debug output (#6940)

Lib/test/test_socket.py

@@ -893,7 +893,7 @@ class GeneralModuleTests(unittest.TestCase):
         )
         for addr in ['0.1.1.~1', '1+.1.1.1', '::1q', '::1::2',
                      '1:1:1:1:1:1:1:1:1']:
-            with self.assertRaises(OSError):
+            with self.assertRaises(OSError, msg=addr):
                 socket.gethostbyname(addr)
             with self.assertRaises(OSError, msg=explanation):
                 socket.gethostbyaddr(addr)