build(deps): bump highlight.js from 9.12.0 to 9.18.5

Bumps [highlight.js](https://github.com/highlightjs/highlight.js) from 9.12.0 to 9.18.5.
- [Release notes](https://github.com/highlightjs/highlight.js/releases)
- [Changelog](https://github.com/highlightjs/highlight.js/blob/9.18.5/CHANGES.md)
- [Commits](https://github.com/highlightjs/highlight.js/compare/9.12.0...9.18.5

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