[main] (backport #18479) Release notes for 9.1.9

[mergify]

Originally this PR was generated with bad last_version (9.1.9 instead of 9.1.8).
Used #18487 to fix it.

---

This is an automatic backport of pull request #18479 done by Mergify.

[mergify]

Cherry-pick of 68b2a3f has failed:

On branch mergify/bp/main/pr-18479
Your branch is up to date with 'origin/main'.

You are currently cherry-picking commit 68b2a3fd.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   docs/release-notes/index.md

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[github-actions]

🤖 GitHub comments

Just comment with:

• run docs-build : Re-trigger the docs validation. (use unformatted text in the comment!)
• /run exhaustive tests : Run the exhaustive tests Buildkite pipeline.

[github-actions]

🔍 Preview links for changed docs

• docs/release-notes/index.md

[andsel]

@mergify backport to 9.2

[mergify]

backport to 9.2

❌ No backport have been created

Details

• Backport to branch to failed

GitHub error: Branch not found

• #18519 [9.2] (backport #18500) [main] (backport #18479) Release notes for 9.1.9 has been created for branch 9.2