build(deps): bump pymdown-extensions from 10.3 to 10.3.1 in /docs

Bumps [pymdown-extensions](https://github.com/facelessuser/pymdown-extensions) from 10.3 to 10.3.1.
- [Release notes](https://github.com/facelessuser/pymdown-extensions/releases)
- [Commits](facelessuser/pymdown-extensions@10.3...10.3.1)

---
updated-dependencies:
- dependency-name: pymdown-extensions
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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