chore(deps): bump tornado from 6.5.4 to 6.5.5 in /hack/api-docs (#6094)

Bumps [tornado](https://github.com/tornadoweb/tornado) from 6.5.4 to 6.5.5.
- [Changelog](https://github.com/tornadoweb/tornado/blob/master/docs/releases.rst)
- [Commits](https://github.com/tornadoweb/tornado/compare/v6.5.4...v6.5.5)

---
updated-dependencies:
- dependency-name: tornado
  dependency-version: 6.5.5
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

hack/api-docs/requirements.txt

@@ -35,7 +35,7 @@ regex==2026.2.28
 requests==2.32.5
 six==1.17.0
 termcolor==3.3.0
-tornado==6.5.4
+tornado==6.5.5
 urllib3==2.6.3
 verspec==0.1.0
 watchdog==6.0.0