bpo-31649: Make IDLE's _htest, _utest parameters keyword-only. (#3839)

diff --git a/Lib/idlelib/config_key.py b/Lib/idlelib/config_key.py
index 5556b76..3a865f8 100644
--- a/Lib/idlelib/config_key.py
+++ b/Lib/idlelib/config_key.py
@@ -14,7 +14,7 @@
     keyerror_title = 'Key Sequence Error'
 
     def __init__(self, parent, title, action, currentKeySequences,
-                 _htest=False, _utest=False):
+                 *, _htest=False, _utest=False):
         """
         action - string, the name of the virtual event these keys will be
                  mapped to