Fixes link to Roles

This closes #2283. This link is probably better, since it's the declarator. The problem is that it maybe is the symptom for a problem, namely, /syntax/role generated at one particular point in time and no longer there for some fluke of the page generation. So thanks a lot for the report, and I'll investigate if that's the case.

Author: JJ

doc/Language/glossary.pod6

@@ -963,9 +963,10 @@ mixed-in when declaring classes that follow that interface. L<Abstract
 classes|#Abstract class> are particular examples of Roles where the
 actual implementation is deferred to the class that uses that Role.
 
-Roles are part of Perl6's L<object system|/language/objects>, and are declared
-using the keyword L<role|/syntax/role> and used in class declaration via
-L<does|/routine/does>.
+Roles are part of Perl6's L<object system|/language/objects>, and are
+declared using the
+L<role|/language/objects#index-entry-declarator_role-Roles> keyword and
+used in class declaration via L<does|/routine/does>.
 
 X<|rule>
 =head1 rule