OptionalroutableTypes: string[]The document type names that can appear in route maps.
When provided, the doc field uses a proper weak reference with to set
to these types. When empty, falls back to a plain object field to avoid
Sanity's "reference type should define at least one accepted type" error.
Creates the route map schema type with the correct reference targets.
Each document is a pre-computed shard mapping document IDs to their resolved URL paths for a specific channel + document type combination.