Add `fields.emptyContent` and allow specifying a `contentField` nested inside object or conditional fields

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 5d2d04619713f36798bcaedbc6d558634a27559e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 13 packages

| Name | Type | | --------------------------- | ----- | | @keystatic/core | Patch | | @keystar/docs | Patch | | @example/astro-content | Patch | | @example/astro | Patch | | @example/localization | Patch | | @example/next-app | Patch | | @example/next-block-builder | Patch | | @example/next-pages | Patch | | @keystatic/remix-test-app | Patch | | keystatic-docs | Patch | | @keystatic/templates-astro | Patch | | @keystatic/templates-nextjs | Patch | | @keystatic/templates-remix | Patch |

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR