bpo-43655: Tkinter and IDLE dialog windows are now recognized as dialogs by window managers on macOS and X Window (#25187)

diff --git a/Lib/idlelib/config_key.py b/Lib/idlelib/config_key.py
index 7510aa9..9ca3a15 100644
--- a/Lib/idlelib/config_key.py
+++ b/Lib/idlelib/config_key.py
@@ -4,6 +4,7 @@
 from tkinter import Toplevel, Listbox, StringVar, TclError
 from tkinter.ttk import Frame, Button, Checkbutton, Entry, Label, Scrollbar
 from tkinter import messagebox
+from tkinter.simpledialog import _setup_dialog
 import string
 import sys
 
@@ -63,6 +64,7 @@ def __init__(self, parent, title, action, current_key_sequences,
         self.resizable(height=False, width=False)
         self.title(title)
         self.transient(parent)
+        _setup_dialog(self)
         self.grab_set()
         self.protocol("WM_DELETE_WINDOW", self.cancel)
         self.parent = parent