Bump cspell from 9.4.0 to 9.6.0 in /eng/common/spelling (#44767)

Bumps [cspell](https://github.com/streetsidesoftware/cspell/tree/HEAD/packages/cspell) from 9.4.0 to 9.6.0.
- [Release notes](https://github.com/streetsidesoftware/cspell/releases)
- [Changelog](https://github.com/streetsidesoftware/cspell/blob/main/packages/cspell/CHANGELOG.md)
- [Commits](https://github.com/streetsidesoftware/cspell/commits/v9.6.0/packages/cspell)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: azure-sdk