Bump sphinx from 6.2.1 to 7.2.6 in /requirements

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 6.2.1 to 7.2.6.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES)
- [Commits](sphinx-doc/sphinx@v6.2.1...v7.2.6)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

requirements/docs.txt

@@ -9,9 +9,9 @@ Pygments==2.16.1 \
     --hash=sha256:13fc09fa63bc8d8671a6d247e1eb303c4b343eaee81d861f3404db2935653692 \
     --hash=sha256:1daff0494820c69bc8941e407aa20f577374ee88364ee10a98fdbe0aece96e29
 # Sphinx is required by sphinxcontrib-httpdomain
-Sphinx==6.2.1 \
-    --hash=sha256:6d56a34697bb749ffa0152feafc4b19836c755d90a7c59b72bc7dfd371b9cc6b \
-    --hash=sha256:97787ff1fa3256a3eef9eda523a63dbf299f7b47e053cfcf684a1c2a8380c912
+Sphinx==7.2.6 \
+    --hash=sha256:1e09160a40b956dc623c910118fa636da93bd3ca0b9876a7b3df90f07d691560 \
+    --hash=sha256:9a5160e1ea90688d5963ba09a2dcd8bdd526620edbb65c328728f1b2228d5ab5
 # alabaster is required by Sphinx
 alabaster==0.7.13 \
     --hash=sha256:1ee19aca801bbabb5ba3f5f258e4422dfa86f82f3e9cefb0859b283cdd7f62a3 \