release 8.5.0

[Pallets release steps](https://palletsprojects.com/contributing/release)

- [x] Decide to make a release.
- [x] Ensure the change log has entries for each user-facing non-docs change, with links to the related issue reports.
- [x] Ensure each issue and PR is in the milestone. 
- [x] verify or trigger [nightly tests](https://github.com/pallets/click/actions/workflows/nightly.yaml)
- [x] Create a release-A.B.C branch.
- [x] Change "Unreleased" to "Released YYYY-MM-DD" in CHANGES.md.
- [x] Remove the ".dev" suffix from the version in pyproject.toml.
- [x] Commit git commit -am 'release version A.B.C' and create a PR.
- [x] Tag `git tag -am 'release version A.B.C' A.B.C` and push `git push upstream A.B.C.`
- [x] Watch the tests pass and build jobs begin.
- [x] Edit the generated draft release page with our standard message template.
- [x] Approve the upload job.
- [x] Merge the PR. Use "create a merge commit", not "squash" or "rebase"!
- [x] Close the milestone.
- [x] Publish the draft release page.
- [x] Merge main into stable (or stable into main): 
- [x] Start the next version(s), creating a change log section, bumping the version in pyproject.toml with the .dev suffix.
- [x] Done!

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