bpo-41300: IDLE - save files with non-ascii chars  (GH-21512)

Fix regression released in 3.9.0b4 and 3.8.4.
diff --git a/Lib/idlelib/NEWS.txt b/Lib/idlelib/NEWS.txt
index 1c5c03d..60f46f6 100644
--- a/Lib/idlelib/NEWS.txt
+++ b/Lib/idlelib/NEWS.txt
@@ -3,6 +3,9 @@
 ======================================
 
 
+bpo-41300: Save files with non-ascii chars.  Fix regression in
+3.9.0b4 and 3.8.4.
+
 bpo-37765: Add keywords to module name completion list.  Rewrite
 Completions section of IDLE doc.
 
diff --git a/Lib/idlelib/iomenu.py b/Lib/idlelib/iomenu.py
index 7641d86..74ebefd 100644
--- a/Lib/idlelib/iomenu.py
+++ b/Lib/idlelib/iomenu.py
@@ -1,3 +1,4 @@
+import io
 import os
 import shlex
 import sys