Docs recommend `fields.document`, but `.document` is deprecated

[evadecker]

Hi!

Getting started with Keystatic for the first time today on an existing Astro installation. I'm following the Astro integration guide which instructs users to add a keystatic.config.ts file with the following:

      schema: {
        title: fields.slug({ name: { label: 'Title' } }),
        content: fields.document({
          label: 'Content',
          formatting: true,
          dividers: true,
          links: true,
          images: true,
        }),
      },

However, TypeScript indicates .document has been deprecated and superseded by fields.markdoc or fields.mdx — which both have different call signatures.

I can figure out how to use the new types, but up-to-date docs would be really helpful for a beginner!

[evadecker]

Thanks for the super speedy fix!