Update Lib/test/test_re.py

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

Author: Abhi210

Lib/test/test_re.py

@@ -1642,7 +1642,7 @@ def s_int(scanner, token): return int(token)
     def test_bug_gh140797(self):
         # gh140797: Capturing groups are not allowed in re.Scanner
 
-        msg = "Cannot use capturing groups in re.Scanner"
+        msg = r"Cannot use capturing groups in re\.Scanner"
         # Capturing group throws an error
         with self.assertRaisesRegex(ValueError, msg):
             Scanner([("(a)b", None)])