code requires variable declarations

Author: coke

doc/Language/objects.pod6

@@ -299,10 +299,12 @@ Method names can be resolved at runtime with the C<.""> operator.
 The syntax used to update C<$.notes> changed in this section with respect
 to the previous L<#Attributes> section. Instead of an assignment:
 
+=for code :preamble<my $vacation>
     $vacation.notes = 'Pack hiking gear and sunglasses!';
 
 we now do a method call:
 
+=for code :preamble<my $trip>
     $trip.notes("First steps");
 
 Overriding the default auto-generated accessor means it is no longer