Eliminated indexing entry

And linked to the one that's indexed automatically. Closes #3861

Author: JJ

doc/Type/Any.pod6

@@ -1438,8 +1438,9 @@ my %hash = 'aa' => 'value', 'Za' => 'second';
 say %hash.collate; # (aa => value Za => second);
 =end code
 
-This method is affected by the X<$*COLLATION> variable, which
-configures the four X<collation levels>. While the Primary, Secondary and
+This method is affected by the
+L<C<$*COLLATION>|/language/variables#index-entry-$*COLLATION> variable, which
+configures the four X<collation levels>. While Primary, Secondary and
 Tertiary mean different things for different scripts, for the Latin script used
 in English they mostly correspond with Primary being Alphabetic, Secondary being
 Diacritics and Tertiary being Case.