chore(deps-dev): Update mkdocs-material requirement from ~=9.6.14 to ~=9.6.15 in /gh-pages (#4851)

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-9.6.15</h2>
<ul>
<li>Updated Mongolian translations</li>
<li>Improved semantic markup of &quot;edit this page&quot; button</li>
<li>Improved info plugin virtual environment resolution</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8291">#8291</a>: Large font size setting throws of breakpoints in JavaScript</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-9.6.15 (2025-07-01)</p>
<ul>
<li>Updated Mongolian translations</li>
<li>Improved semantic markup of &quot;edit this page&quot; button</li>
<li>Improved info plugin virtual environment resolution</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8291">#8291</a>: Large font size setting throws of breakpoints in JavaScript</li>
</ul>
<p>mkdocs-material-9.6.14 (2025-05-13)</p>
<ul>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8215">#8215</a>: Social plugin crashes when CairoSVG is updated to 2.8</li>
</ul>
<p>mkdocs-material-9.6.13 (2025-05-10)</p>
<ul>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8204">#8204</a>: Annotations showing list markers in print view</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8153">#8153</a>: Improve style of cardinality symbols in Mermaid.js ER diagrams</li>
</ul>
<p>mkdocs-material-9.6.12 (2025-04-17)</p>
<ul>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8158">#8158</a>: Flip footnote back reference icon for right-to-left languages</li>
</ul>
<p>mkdocs-material-9.6.11 (2025-04-01)</p>
<ul>
<li>Updated Docker image to latest Alpine Linux</li>
<li>Bump required Jinja version to 3.1</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8133">#8133</a>: Jinja filter <code>items</code> not available (9.6.10 regression)</li>
<li>Fixed <a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8128">#8128</a>: Search plugin not entirely disabled via enabled setting</li>
</ul>
<p>mkdocs-material-9.6.10 (2025-03-30)</p>
<p>This version is a pure refactoring release, and does not contain new features
or bug fixes. It strives to improve the compatibility of our templates with
alternative Jinja-like template engines that we're currently exploring,
including minijinja.</p>
<p>Additionally, it replaces several instances of Python function invocations
with idiomatic use of template filters. All instances where variables have
been mutated inside templates have been replaced. Most changes have been made
in partials, and only a few in blocks, and all of them are fully backward
compatible, so no changes to overrides are necessary.</p>
<p>Note that this release does not replace the Jinja template engine with
minijinja. However, our templates are now 99% compatible with minijinja,
which means we can explore alternative Jinja-compatible implementations.
Additionally, immutability and removal of almost all Python function
invocations means much more idiomatic templating.</p>
<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>
</ul>

</blockquote>
<p>... (truncated)</p>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/e8a63311e8549124c27860dd811c57029d76ccf7"><code>e8a6331</code></a> Prepare 9.6.15 release</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/1f7a4962340ef0434e46606a7ac7ca197079bcc1"><code>1f7a496</code></a> Fixed breakpoint unit for media queries in JS</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/462bf384fff92c85a2c4624696edafedaa19194b"><code>462bf38</code></a> Updated dependencies</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/2b0417f7c42ad1e28e3fc8051e163bf689000a77"><code>2b0417f</code></a> Updated info plugin to exclude guessed venv paths (<a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8286">#8286</a>)</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/2b428604623bf384145ac1012d4d88d3d3f8ce5d"><code>2b42860</code></a> Fixed feedback widget not mounting with instant navigation (<a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8275">#8275</a>)</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/74f6007e319ed4768697e74ad3d73bc8b0b298cd"><code>74f6007</code></a> Updated JSON schema (<a href="https://redirect.github.com/squidfunk/mkdocs-material/issues/8264">#8264</a>)</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/2313e0c536a1eaf40b922161aab42939d9384498"><code>2313e0c</code></a> Also add Asahi Linux</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/371b107ed116dffe95de7c07d05c9a3e5b7212da"><code>371b107</code></a> Added more open-source projects</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/406a3ad81a87dbb4922b799e6f5fc16028a8186b"><code>406a3ad</code></a> Updated Premium sponsors</li>
<li><a href="https://github.com/squidfunk/mkdocs-material/commit/462c94e88f89331c0484643d33aabdeba95d7394"><code>462c94e</code></a> Updated Mongolian translations</li>
<li>Additional commits viewable in <a href="https://github.com/squidfunk/mkdocs-material/compare/9.6.14...9.6.15">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~=9.6.14
+mkdocs-material~=9.6.15
 mkdocs-git-revision-date-plugin~=0.3.2