Update sphinx requirement from !=5.1.0,<7.3.6,>=4 to >=4,!=5.1.0,<7.3.7

Updates the requirements on [sphinx](https://github.com/sphinx-doc/sphinx) to permit the latest version.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v4.0.0...v7.3.6)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

pyproject.toml

@@ -39,7 +39,7 @@ doc = [
     "doc8>=0.9,<1.2",  # Ensures clean documentation formatting
     "furo>=2022.4.7",  # A clean customisable Sphinx documentation theme.
     "rstcheck[sphinx,toml]>=5.0,<6.3",  # ReStructuredText linter
-    "sphinx>=4,!=5.1.0,<7.3.6",
+    "sphinx>=4,!=5.1.0,<7.3.7",
     "sphinx-autoapi>=1.8,<3.1",
     "sphinx-issues>=1.2,<4.2",
     "sphinx-autodoc-typehints>1.19,<2.1.1",