public virtual OnForeignKeyRemovedNode VisitOnForeignKeyRemoved(OnForeignKeyRemovedNode node) => node;
 public override OnForeignKeyRemovedNode VisitOnForeignKeyRemoved(OnForeignKeyRemovedNode node)
 {
     Dispatcher._immediateConventionScope.OnForeignKeyRemoved(node.EntityTypeBuilder, node.ForeignKey);
     return(null);
 }