update migration guide

Author: gavinking

migration-guide.adoc

@@ -468,6 +468,7 @@ In Hibernate 7, these SQL `UPDATE` statements only occur if the `@OrderColumn` i
 ** Removed `org.hibernate.Interceptor#getEntity(String, Serializable)` in favour of `org.hibernate.Interceptor#getEntity(String, Serializable)`
 ** Removed `org.hibernate.metamodel.spi.MetamodelImplementor` in favor of `org.hibernate.metamodela.MappingMetmodel` or `org.hibernate.metamodel.model.domain.JpaMetamodel`
 ** Removed `org.hibernate.Metamodel` in favor of `org.hibernate.metamodel.model.domain.JpaMetamodel`
+** Removed `NaturalIdLoadAccess.using(Map)` and `NaturalIdMultiLoadAccess.compoundValue()` in favor of `Map.of()`
 
 * Settings
 ** Removed `hibernate.mapping.precedence` and friends