Bump tornado from 6.4 to 6.4.1 in /docs

Bumps [tornado](https://github.com/tornadoweb/tornado) from 6.4 to 6.4.1.
- [Changelog](https://github.com/tornadoweb/tornado/blob/master/docs/releases.rst)
- [Commits](tornadoweb/tornado@v6.4.0...v6.4.1)

---
updated-dependencies:
- dependency-name: tornado
  dependency-type: indirect
...

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

docs/requirements.txt

@@ -81,7 +81,7 @@ sphinxcontrib-spelling==8.0.0
     # via -r requirements.in
 sphinxext-opengraph==0.9.0
     # via -r requirements.in
-tornado==6.4
+tornado==6.4.1
     # via livereload
 urllib3==2.2.2
     # via requests