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.

Author: terryjreedy

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