Description

• Closes type errors using extended i18n schema #1787
• Fixes type inference for labels when a user provides additional translation strings by extending Starlight’s i18n schema
• Previously these were statically typed based on our default schema shape. Now these should infer from the content collection type if configured.

Testing

To test this, I followed these manual steps:

1. Extended the i18n schema in docs/src/content/config.ts with an extra field:

   schema: i18nSchema({ extend: z.object({ test: z.string() }) }),

2. I added a test file at docs/src/content/i18n/lang.yml to make Astro detect the collection, and added some content:

   test: test

3. I created a test component using our overrides prop type to see if it would pick up the extended field in labels:

   ---
   import type { Props } from '@astrojs/starlight/props';
   
   Astro.props.labels.test
   //                 ^ string
   ---