docs: Fix syntax highlighting for `Ash.Type` code blocks

[sevenseacat]

Notices that some of the code blocks here https://hexdocs.pm/ash/Ash.Type.html weren't syntax-highlighted - they are now :)

Contributor checklist

• [ ] Bug fixes include regression tests
• [ ] Chores
• [x] Documentation changes
• [ ] Features include unit/acceptance tests
• [ ] Refactoring
• [ ] Update dependencies

[barnabasJ]

🚀 Thank you for your contribution! 🚀