chore(deps-dev): Update mkdocs-material requirement from ~=9.6.7 to ~=9.6.9 in /gh-pages (#4796)

Updates the requirements on [mkdocs-material](https://github.com/squidfunk/mkdocs-material) to permit the latest version.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a href="https://github.com/squidfunk/mkdocs-material/releases">mkdocs-material's releases</a>.</em></p>
<blockquote>
<h2>mkdocs-material-9.6.9</h2>
<ul>
<li>Updated Serbo-Croatian translations</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8086">#8086</a>: Custom SVG icons containing hashes break rendering</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8067">#8067</a>: Drawer has gap on right side in Firefox on some OSs</li>
</ul>
</blockquote>
</details>
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a href="https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG">mkdocs-material's changelog</a>.</em></p>
<blockquote>
<p>mkdocs-material-9.6.9 (2025-03-17)</p>
<ul>
<li>Updated Serbo-Croatian translations</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8086">#8086</a>: Custom SVG icons containing hashes break rendering</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8067">#8067</a>: Drawer has gap on right side in Firefox on some OSs</li>
</ul>
<p>mkdocs-material-9.6.8+insiders-4.53.16 (2025-03-13)</p>
<ul>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8019">#8019</a>: Tooltips have precedence over instant previews</li>
</ul>
<p>mkdocs-material-9.6.8 (2025-03-13)</p>
<ul>
<li>Added Welsh translations</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8076">#8076</a>: Privacy plugin crashes if HTTP download fails</li>
</ul>
<p>mkdocs-material-9.6.7 (2025-03-03)</p>
<ul>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8056">#8056</a>: Error in backrefs implementation (9.6.6 regression)</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8054">#8054</a>: Unescaped quotes in ARIA labels of table of contents</li>
</ul>
<p>mkdocs-material-9.6.6 (2025-03-01)</p>
<ul>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8040">#8040</a>: Privacy plugin not replacing exteral assets (9.6.5 regression)</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8031">#8031</a>: Replace unmaintained regex package in search plugin</li>
</ul>
<p>mkdocs-material-9.6.5 (2025-02-20)</p>
<ul>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8016">#8016</a>: Tags listing not showing when when file name has spaces</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8012">#8012</a>: Privacy plugin crashes if HTTP download fails</li>
</ul>
<p>mkdocs-material-9.6.4 (2025-02-12)</p>
<ul>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/7985">#7985</a>: Blog content sometimes not stretching to full width</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/7978">#7978</a>: Navigation rendering bug in Safari 18.3</li>
</ul>
<p>mkdocs-material-9.6.3 (2025-02-07)</p>
<ul>
<li>Fixed rendering of arrow heads in Mermaid.js class diagrams</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/7960">#7960</a>: Tags plugin crashes on numeric metadata titles</li>
</ul>
<p>mkdocs-material-9.6.2 (2025-02-03)</p>
<ul>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/7955">#7955</a>: Excessively long words don't break on narrow screens</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/7947">#7947</a>: Scope setting interferes with outdated version banner</li>
</ul>
<p>mkdocs-material-9.6.1 (2025-01-31)</p>
<ul>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/7943">#7943</a>: Tags plugin crashing due to merge error</li>
</ul>
<p>mkdocs-material-9.6.0 (2025-01-31)</p>

</blockquote>
<p>... (truncated)</p>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/646c7ab30d2890c1b27c9b6444156bb1104a372e"><code>646c7ab</code></a> Prepare 9.6.9 release</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/27d57ea184ad31777a632bb52b8c2b8a80cdb128"><code>27d57ea</code></a> Updated twemoji cdn for icon search index (<a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8093">#8093</a>)</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/091865798faa41018f014dae8d7a8add3f121d56"><code>0918657</code></a> Fixed <code>build:all</code> output on Windows (<a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8089">#8089</a>)</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/0e75aef9ea9028dc5a2dea34fb5da8afb14911ae"><code>0e75aef</code></a> Updated Serbo-Croatian translations</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/52b584f9cbe85040841010533b56abb39b5b4052"><code>52b584f</code></a> Added urlencode to fix # in custom icons (<a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8087">#8087</a>)</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/3296cdf203ba2886338d285a15121ab2fa95e6e9"><code>3296cdf</code></a> Fixed sidebar on Firefox mobile</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/502ef2f788ca84a7686e6dcee7aaf5b2fe11e1db"><code>502ef2f</code></a> Updated Insiders changelog</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/a43d2235b1dd16b447c3a04454070b328b509a81"><code>a43d223</code></a> Prepare 9.6.8 release</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/76a66b7597fc89c7c83e597167e3ff61b9afaac3"><code>76a66b7</code></a> Fixed error in translations partial</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/1c5e112549abd05fce7cc611e971a29ba3b62e66"><code>1c5e112</code></a> Integrated Welsh translations</li>
<li>Additional commits viewable in <a href="https://github.com/squidfunk/mkdocs-material/compare/9.6.7...9.6.9">compare view</a></li>
</ul>
</details>
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gh-pages/requirements-dev.txt

@@ -1,4 +1,4 @@
 mkdocs~=1.6.1
 mkdocs-awesome-pages-plugin~=2.10.1
-mkdocs-material~=9.6.7
+mkdocs-material~=9.6.9
 mkdocs-git-revision-date-plugin~=0.3.2