=over 4
-=item B<subtype 'Name' => as 'Parent' => where { } ...>
+=item B<< subtype 'Name' => as 'Parent' => where { } ... >>
This creates a named subtype.
The valid hashref keys are C<as> (the parent), C<where>, C<message>,
and C<optimize_as>.
-=item B<subtype as 'Parent' => where { } ...>
+=item B<< subtype as 'Parent' => where { } ... >>
This creates an unnamed subtype and will return the type
constraint meta-object, which will be an instance of