Bump docutils from 0.16 to 0.19 in /docs

Bumps [docutils](https://docutils.sourceforge.io/) from 0.16 to 0.19.

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

docs/requirements.txt

@@ -1,5 +1,5 @@
 archspec==0.1.3
-docutils==0.16 # https://github.com/sphinx-doc/sphinx/issues/9001
+docutils==0.19 # https://github.com/sphinx-doc/sphinx/issues/9001
 jsonschema==3.2.0
 semver==2.13.0
 Sphinx==4.3.1