Bump tornado from 6.4.1 to 6.4.2 in /docs

Bumps [tornado](https://github.com/tornadoweb/tornado) from 6.4.1 to 6.4.2.
- [Changelog](https://github.com/tornadoweb/tornado/blob/v6.4.2/docs/releases.rst)
- [Commits](tornadoweb/tornado@v6.4.1...v6.4.2)

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

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

docs/requirements.txt

@@ -60,16 +60,16 @@ snowballstemmer==2.2.0
     # via sphinx
 sphinx==7.1.2
     # via
-    #   -r docs/requirements.in
+    #   -r requirements.in
     #   sphinx-autobuild
     #   sphinx-immaterial
     #   sphinx-intl
 sphinx-autobuild==2021.3.14
-    # via -r docs/requirements.in
+    # via -r requirements.in
 sphinx-immaterial==0.11.14
-    # via -r docs/requirements.in
+    # via -r requirements.in
 sphinx-intl==2.2.0
-    # via -r docs/requirements.in
+    # via -r requirements.in
 sphinxcontrib-applehelp==1.0.4
     # via sphinx
 sphinxcontrib-devhelp==1.0.2
@@ -82,7 +82,7 @@ sphinxcontrib-qthelp==1.0.3
     # via sphinx
 sphinxcontrib-serializinghtml==1.1.5
     # via sphinx
-tornado==6.4.1
+tornado==6.4.2
     # via livereload
 typing-extensions==4.12.2
     # via