[3.7] Fix collections ABC deprecation notice by Anthchirp · Pull Request #25280 · python/cpython

The deprecation originally slated for 3.9 was deferred to 3.10
(bpo-39674, pythonGH-18545). However the deprecation notice in the release
was left as is, and still indicates deprecation with 3.9.

Also add a missing space in the message.