Bump lxml-html-clean in /docs in the pip group across 1 directory (#7452)

Bumps the pip group with 1 update in the /docs directory: [lxml-html-clean](https://github.com/fedora-python/lxml_html_clean).


Updates `lxml-html-clean` from 0.4.0 to 0.4.4
- [Changelog](https://github.com/fedora-python/lxml_html_clean/blob/main/CHANGES.rst)
- [Commits](fedora-python/lxml_html_clean@0.4.0...0.4.4)

---
updated-dependencies:
- dependency-name: lxml-html-clean
  dependency-version: 0.4.4
  dependency-type: direct:production
  dependency-group: pip
...

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Author: dependabot[bot]

docs/requirements.txt

@@ -10,4 +10,4 @@ sphinx-copybutton==0.5.2
 nbconvert==7.17.0
 tinycss2>=1.1.0,<1.5
 lxml==5.2.1
-lxml_html_clean==0.4.0
+lxml_html_clean==0.4.4