🤖 Update myst-parser requirement from <4,>=3 to >=3,<5

Updates the requirements on [myst-parser](https://github.com/executablebooks/MyST-Parser) to permit the latest version.
- [Release notes](https://github.com/executablebooks/MyST-Parser/releases)
- [Changelog](https://github.com/executablebooks/MyST-Parser/blob/master/CHANGELOG.md)
- [Commits](executablebooks/MyST-Parser@v3.0.0...v4.0.0)

---
updated-dependencies:
- dependency-name: myst-parser
  dependency-type: direct:production
...

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

requirements/docs.txt

@@ -1,5 +1,5 @@
 sphinx<9
 furo>=2024.4.27,<2024.8
 sphinx-copybutton~=0.5
-myst-parser>=3,<4
+myst-parser>=3,<5
 enum-tools[sphinx]==0.12.0