Bump sphinxcontrib-spelling from 7.1.0 to 7.2.1
Bump sphinxcontrib-spelling from 7.1.0 to 7.2.1

Bumps [sphinxcontrib-spelling](https://github.com/sphinx-contrib/spelling) from 7.1.0 to 7.2.1.
- [Release notes](https://github.com/sphinx-contrib/spelling/releases)
- [Commits](https://github.com/sphinx-contrib/spelling/compare/7.1.0...7.2.1)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
aio-libs/frozenlist,aio-libs/frozenlist