bpo-43013: Fix old tkinter module names in idlelib (GH-24326)

Lowercase 'tkColorChooser', 'tkFileDialog', 'tkSimpleDialog', and
'tkMessageBox' and remove 'tk'.  Just lowercase 'tkFont' as 'font'
is already used.  Adjust import.
diff --git a/Lib/idlelib/searchengine.py b/Lib/idlelib/searchengine.py
index a50038e..eddef58 100644
--- a/Lib/idlelib/searchengine.py
+++ b/Lib/idlelib/searchengine.py
@@ -2,7 +2,7 @@
 import re
 
 from tkinter import StringVar, BooleanVar, TclError
-import tkinter.messagebox as tkMessageBox
+from tkinter import messagebox
 
 def get(root):
     '''Return the singleton SearchEngine instance for the process.
@@ -96,7 +96,7 @@ def report_error(self, pat, msg, col=None):
             msg = msg + "\nPattern: " + str(pat)
         if col is not None:
             msg = msg + "\nOffset: " + str(col)
-        tkMessageBox.showerror("Regular expression error",
+        messagebox.showerror("Regular expression error",
                                msg, master=self.root)
 
     def search_text(self, text, prog=None, ok=0):