Bump highlight.js from 9.15.8 to 9.15.9
Bump highlight.js from 9.15.8 to 9.15.9

Bumps [highlight.js](https://github.com/highlightjs/highlight.js) from 9.15.8 to 9.15.9.
- [Release notes](https://github.com/highlightjs/highlight.js/releases)
- [Changelog](https://github.com/highlightjs/highlight.js/blob/master/CHANGES.md)
- [Commits](https://github.com/highlightjs/highlight.js/compare/9.15.8...9.15.9)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
crowi/crowi,crowi/crowi,crowi/crowi