Update docs for migration function

packages/data/src/plugins/persistence/index.js

@@ -226,8 +226,10 @@ function persistencePlugin( registry, pluginOptions ) {
  * Move the 'features' object in local storage from the sourceStoreName to the
  * interface store.
  *
- * @param {*} persistence
- * @param {*} sourceStoreName
+ * @param {Object} persistence     The persistence interface.
+ * @param {string} sourceStoreName The name of the store that has persisted
+ *                                 preferences to migrate to the interface
+ *                                 package.
  */
 export function migrateFeaturePreferencesToInterfaceStore(
 	persistence,