Link to curated release notes in patch release notes

[NickGerleman]

Right now our patch releases look like the below

We have a high enough release frequency that the last major release is often off the first page. This makes it hard to find the manually curated documentation for an overall release. We can fix this by adding a description to the generated release notes, with a link to the curated release notes.

[NickGerleman]

The code to do this is in @rnw-scripts/create-github-releases which is a pretty simple script. New versions of the script are automatically picked up by any previous branch.