chore: bump mkdocs-material from 9.5.14 to 9.5.15

Bumps [mkdocs-material](https://github.com/squidfunk/mkdocs-material) from 9.5.14 to 9.5.15.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Commits](https://github.com/squidfunk/mkdocs-material/compare/9.5.14...9.5.15)

---
updated-dependencies:
- dependency-name: mkdocs-material
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

docs/requirements.txt

@@ -1,4 +1,4 @@
 # Force rtfd to use a recent version of mkdocs
 mkdocs==1.5.3
 pymdown-extensions==10.7.1
-mkdocs-material==9.5.14
+mkdocs-material==9.5.15

pyproject.toml

@@ -47,7 +47,7 @@ dev = [
   "ruff==0.3.3",
   "djlint==1.34.1",
   "mkdocs==1.5.3",
-  "mkdocs-material==9.5.14",
+  "mkdocs-material==9.5.15",
   "vermin==1.6.0",
   "pymdown-extensions==10.7.1",
   "isort==5.13.2",