[3.10] bpo-44342: [Enum] improve test, add andrei kulakov to ACKS (GH-26726)

* [3.10] [Enum] improve test, add andrei kulakov to ACKS (GH-26726).
(cherry picked from commit cb2014f2077c92c35486bf0db7e646a68478a7a5)

Co-authored-by: Ethan Furman <ethan@stoneleaf.us>
diff --git a/Lib/enum.py b/Lib/enum.py
index 49c46ea..9077798 100644
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -1637,7 +1637,7 @@ def __call__(self, enumeration):
                     else:
                         value = 'combined values of 0x%x' % missing_value
                     raise ValueError(
-                            'invalid Flag %r: %s %s [use `enum.show_flag_values(value)` for details]'
+                            'invalid Flag %r: %s %s [use enum.show_flag_values(value) for details]'
                             % (cls_name, alias, value)
                             )
         return enumeration