bpo-35660: Fix imports in idlelib.window (#11434)

* bpo-35660: IDLE: Remove * import from window.py

* sys was being imported through the *, so also added an import sys.

* Update 2019-01-04-19-14-29.bpo-35660.hMxI7N.rst

Anyone who wants details can check the issue, where I added the point about the sys import bug.
diff --git a/Lib/idlelib/window.py b/Lib/idlelib/window.py
index b2488b2..460d5b6 100644
--- a/Lib/idlelib/window.py
+++ b/Lib/idlelib/window.py
@@ -1,4 +1,5 @@
-from tkinter import *
+from tkinter import Toplevel, TclError
+import sys
 
 
 class WindowList: