Add docs

docs/development/core/server/kibana-plugin-core-server.md

@@ -255,6 +255,7 @@ The plugin integrates with the core system via lifecycle events: `setup`<!-- -->
 |  [SavedObjectsClientFactoryProvider](./kibana-plugin-core-server.savedobjectsclientfactoryprovider.md) | Provider to invoke to retrieve a [SavedObjectsClientFactory](./kibana-plugin-core-server.savedobjectsclientfactory.md)<!-- -->. |
 |  [SavedObjectsClientWrapperFactory](./kibana-plugin-core-server.savedobjectsclientwrapperfactory.md) | Describes the factory used to create instances of Saved Objects Client Wrappers. |
 |  [SavedObjectsFieldMapping](./kibana-plugin-core-server.savedobjectsfieldmapping.md) | Describe a [saved object type mapping](./kibana-plugin-core-server.savedobjectstypemappingdefinition.md) field.<!-- -->Please refer to [elasticsearch documentation](https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-types.html) For the mapping documentation |
+|  [SavedObjectUnsanitizedDoc](./kibana-plugin-core-server.savedobjectunsanitizeddoc.md) | We want to have two types, one that guarantees a "references" attribute will exist and one that allows it to be null. Since we're not migrating all the saved objects to have a "references" array, we need to support the scenarios where it may be missing (ex migrations). |
 |  [ScopeableRequest](./kibana-plugin-core-server.scopeablerequest.md) | A user credentials container. It accommodates the necessary auth credentials to impersonate the current user.<!-- -->See [KibanaRequest](./kibana-plugin-core-server.kibanarequest.md)<!-- -->. |
 |  [SharedGlobalConfig](./kibana-plugin-core-server.sharedglobalconfig.md) |  |
 |  [StartServicesAccessor](./kibana-plugin-core-server.startservicesaccessor.md) | Allows plugins to get access to APIs available in start inside async handlers. Promise will not resolve until Core and plugin dependencies have completed <code>start</code>. This should only be used inside handlers registered during <code>setup</code> that will only be executed after <code>start</code> lifecycle. |

src/core/server/server.api.md

@@ -1630,8 +1630,6 @@ export interface SavedObjectMigrationContext {
     log: SavedObjectsMigrationLogger;
 }
 
-// Warning: (ae-forgotten-export) The symbol "SavedObjectUnsanitizedDoc" needs to be exported by the entry point index.d.ts
-//
 // @public
 export type SavedObjectMigrationFn = (doc: SavedObjectUnsanitizedDoc, context: SavedObjectMigrationContext) => SavedObjectUnsanitizedDoc;
 
@@ -2227,6 +2225,9 @@ export class SavedObjectTypeRegistry {
     registerType(type: SavedObjectsType): void;
     }
 
+// @public
+export type SavedObjectUnsanitizedDoc = SavedObjectDoc & Partial<Referencable>;
+
 // @public
 export type ScopeableRequest = KibanaRequest | LegacyRequest | FakeRequest;