fix(argparse): apply suggestions from code review

Co-authored-by: sobolevn <mail@sobolevn.me>

Author: mattwang44

Lib/argparse.py

@@ -966,7 +966,7 @@ def format_usage(self):
 
     def _check_compatibility(self, container):
         if '-' not in container.prefix_chars:
-            raise ValueError(f"BooleanOptionalAction requires '-' in prefix_chars.")
+            raise ValueError("BooleanOptionalAction requires '-' in prefix_chars.")
 
 
 class _StoreAction(Action):

Lib/test/test_argparse.py

@@ -797,7 +797,7 @@ def test_invalid_name(self):
 
     def test_prefix_chars_incompatibility(self):
         parser = argparse.ArgumentParser(prefix_chars='+')
-        with self.assertRaises(ValueError) as cm:
+        with self.assertRaisesRegex(ValueError, ...) as cm:
             parser.add_argument('++foo', action=argparse.BooleanOptionalAction)
         self.assertEqual(str(cm.exception),
                          "BooleanOptionalAction requires '-' in prefix_chars.")