gh-89520: IDLE - Use self instead of module-level idleConf in GetExtensionKeys

GetExtensionKeys is a method on IdleConf. Using the module-level
singleton idleConf instead of self is inconsistent with every other
method in the class.

Author: gpshead

Lib/idlelib/config.py

@@ -477,7 +477,7 @@ def GetExtensionKeys(self, extension_name):
         where previously used bindings are disabled.
         """
         bindings_section = f'{extension_name}_cfgBindings'
-        current_keyset = idleConf.GetCurrentKeySet()
+        current_keyset = self.GetCurrentKeySet()
         extension_keys = {}
 
         event_names = set()