[issue37309] idlelib/NEWS.txt for 3.9.0 and backports

[Terry J. Reedy]

Change by Terry J. Reedy <tjreedy at udel.edu>:


----------
keywords: +patch
pull_requests: +16475
stage: commit review -> patch review
pull_request: https://github.com/python/cpython/pull/16947

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue37309>
_______________________________________