Issue #7472: ISO-2022 charsets now consistently use 7bit CTE.

Fixed a typo in the email.encoders module so that messages output using
an ISO-2022 character set will use a content-transfer-encoding of
7bit consistently.  Previously if the input data had any eight bit
characters the output data would get marked as 8bit even though it
was actually 7bit.
diff --git a/Misc/NEWS b/Misc/NEWS
index ed6bccb..c95076e 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -15,6 +15,10 @@
 Library
 -------
 
+- Issue #7472: Fixed typo in email.encoders module; messages using ISO-2022
+  character sets will now consistently use a Content-Transfer-Encoding of
+  7bit rather than sometimes being marked as 8bit.
+
 - Issue #8330: Fix expected output in test_gdb.
 
 - Issue #8374: Update the internal alias table in the :mod:`locale` module