Release notes in GitHub have significant-newlines, which makes our
canonical `changelog.md` content look not-great -- and the relative
links are also broken, as they have the wrong relative path.
Switch to linking to the canonical release notes on ReadTheDocs, now
that those have proper anchors.
- Updates `.prettierignore` for the new directory.
- Updates any reference to the API documentation directory for
markdown files to be `api_docs/` instead of `zerver/api/`.
- Removes a reference link from `docs/documentation/api.md` that
hasn't referenced anything in the text since commit 0542c60.
- Update rendering of API documentation for new directory.
These suffixes suppress some checks in the process, but still generate
and upload a tarball, push a tag, and make a Github prerelease.
`upload-release` already understands that anything with a suffix never
becomes the "latest" release.
Alex Vandiver
Lauryn Menard
Tim Abbott
Matt Keller