[3.13] gh-136061: Simplify idlelib.editor.EditorWindow.load_extension methodname processing (GH-156913)

(cherry picked from commit 0625799)

Co-authored-by: John <johnzhou721@gmail.com>

Author: miss-islington

Lib/idlelib/editor.py

@@ -1175,12 +1175,7 @@ def load_extension(self, name):
         if keydefs:
             self.apply_bindings(keydefs)
             for vevent in keydefs:
-                methodname = vevent.replace("-", "_")
-                while methodname[:1] == '<':
-                    methodname = methodname[1:]
-                while methodname[-1:] == '>':
-                    methodname = methodname[:-1]
-                methodname = methodname + "_event"
+                methodname = vevent.strip("<>").replace("-", "_") + "_event"
                 if hasattr(ins, methodname):
                     self.text.bind(vevent, getattr(ins, methodname))