Source file f.flush() after writing; trying to avoid lossage if user

kills GUI.  Report from B. Sherwood.  Backport to 2.3.4.

Lib/idlelib/IOBinding.py

@@ -377,6 +377,7 @@ class IOBinding:
         try:
             f = open(filename, "wb")
             f.write(chars)
+            f.flush()
             f.close()
             return True
         except IOError, msg:

Lib/idlelib/NEWS.txt

@@ -3,6 +3,9 @@ What's New in IDLE 1.2a0?
 
 *Release date: XX-XXX-2006*
 
+- Source file f.flush() after writing; trying to avoid lossage if user
+  kills GUI.
+
 - Options / Keys / Advanced dialog made functional.  Also, allow binding
   of 'movement' keys.
 
@@ -70,7 +73,7 @@ What's New in IDLE 1.2a0?
 
 - Improve error handling when .idlerc can't be created (warn and exit).
 
-- The GUI was hanging if the shell window was closed while a raw_input() 
+- The GUI was hanging if the shell window was closed while a raw_input()
   was pending.  Restored the quit() of the readline() mainloop().
   http://mail.python.org/pipermail/idle-dev/2004-December/002307.html