chore(deps-dev): bump the astro group with 3 updates

Bumps the astro group with 3 updates: [@astrojs/check](https://github.com/withastro/astro/tree/HEAD/packages/language-tools/astro-check), [@astrojs/mdx](https://github.com/withastro/astro/tree/HEAD/packages/integrations/mdx) and [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro).


Updates `@astrojs/check` from 0.9.5 to 0.9.6
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/language-tools/astro-check/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/@astrojs/check@0.9.6/packages/language-tools/astro-check)

Updates `@astrojs/mdx` from 4.3.9 to 4.3.12
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/integrations/mdx/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/@astrojs/mdx@4.3.12/packages/integrations/mdx)

Updates `astro` from 5.15.6 to 5.16.3
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/astro/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/astro@5.16.3/packages/astro)

---
updated-dependencies:
- dependency-name: "@astrojs/check"
  dependency-version: 0.9.6
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: astro
- dependency-name: "@astrojs/mdx"
  dependency-version: 4.3.12
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: astro
- dependency-name: astro
  dependency-version: 5.16.3
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: astro
...

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Author: dependabot[bot]