Update the release script to remind releaser to check for special release notes. (#16461)

* Add reminder to check special release notes board in release script

* Newsfile

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

* Update release.py

* Bah, black

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Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>