Broken Release Notes link on /docs/guide/writing/style-guides.md

[Anne K]

In the Release Notes section of the Write the Docs Style Guide, there is a link for Slack that says "more about their release note style".

This link goes to an error page from Slack. I am unable to find a comparable page, so this link should probably just be removed.

[Barrie Byron]

thank you fixed! 2d4e92c#diff-b7c11c911d9fa463a9e5b6b5f0b53bc0fd25b948b7589afbf3c6ee435d48e9b8R146