bpo-45193: Restore IDLE completion boxes on Ubuntu (GH-28343)

The line that should not have been needed on macOS tk 8.6.8 but was,
should not be a problem on Ubuntu, but is.  It is not needed on macOS
tk 8.6.11, installed with 3.10.  Disable it but leave it for
now in case some system needs it.
(cherry picked from commit 1afc7b3)

Co-authored-by: Terry Jan Reedy <[email protected]>

Author: 2 people

Lib/idlelib/autocomplete_w.py

@@ -206,7 +206,7 @@ def show_window(self, comp_lists, index, complete, mode, userWantsWin):
         scrollbar.config(command=listbox.yview)
         scrollbar.pack(side=RIGHT, fill=Y)
         listbox.pack(side=LEFT, fill=BOTH, expand=True)
-        acw.update_idletasks() # Need for tk8.6.8 on macOS: #40128.
+        #acw.update_idletasks() # Need for tk8.6.8 on macOS: #40128.
         acw.lift()  # work around bug in Tk 8.5.18+ (issue #24570)
 
         # Initialize the listbox selection