Fix a link to a class

Author: coke

doc/Language/signatures.rakudoc

@@ -1120,7 +1120,7 @@ One can also constrain the arguments subject to a C<Capture> by using a sub-sign
     d(41);
     # OUTPUT: «Too few positionals passed to 'd'; expected 2 arguments but got 1 in sub-signature or parameter cap␤ ...»
 
-I<Unbound> C<Captures> are often used in C<proto> definitions (like C<proto foo (|) {*}>) to
+I<Unbound> L<C<Capture>|/type/Capture>s are often used in C<proto> definitions (like C<proto foo (|) {*}>) to
 indicate that the routine's L<C<multi> definitions|/syntax/multi> can have any L<type
 constraints|#Type_constraints>. See L<proto|/language/functions#proto> for an
 example.