Bump ruff from 0.5.5 to 0.6.9

Bumps [ruff](https://github.com/astral-sh/ruff) from 0.5.5 to 0.6.9.
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.5.5...0.6.9)

---
updated-dependencies:
- dependency-name: ruff
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

pyproject.toml

@@ -56,7 +56,7 @@ whoosh = [
     "whoosh",
 ]
 lint = [
-    "ruff==0.5.5",
+    "ruff==0.6.9",
     "mypy",
     "types-docutils",
 ]