npm: bump typedoc-plugin-markdown from 4.2.5 to 4.2.9

Bumps [typedoc-plugin-markdown](https://github.com/typedoc2md/typedoc-plugin-markdown/tree/HEAD/packages/typedoc-plugin-markdown) from 4.2.5 to 4.2.9.
- [Release notes](https://github.com/typedoc2md/typedoc-plugin-markdown/releases)
- [Changelog](https://github.com/typedoc2md/typedoc-plugin-markdown/blob/main/packages/typedoc-plugin-markdown/CHANGELOG.md)
- [Commits](https://github.com/typedoc2md/typedoc-plugin-markdown/commits/typedoc-plugin-markdown@4.2.9/packages/typedoc-plugin-markdown)

---
updated-dependencies:
- dependency-name: typedoc-plugin-markdown
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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