PATCH: S04 - unary C<=> is not slurpy

Based on an off-list discussion, it turns out that unary C<=>
is not slurpy as mentioned in S04.  The following patch to S04
corrects this; I've already applied the patch but thought I'd
pass it by p6l for review/comments/reactions.

Pm

• PATCH: S04 - unary C<=> is not slurpy by Patrick R. Michaud
• Re: PATCH: S04 - unary C<=> is not slurpy by Autrijus Tang
• Re: PATCH: S04 - unary C<=> is not slurpy by Damian Conway