Remove link to non-existant Cool method

Author: coke

doc/Language/5to6-perlvar.rakudoc

@@ -211,7 +211,7 @@ for $*KERNEL, $*DISTRO, $*VM -> $what {
 # version 2017.11 named moar by The MoarVM Team
 =end code
 
-The L<C<Cool.Str> method|/type/Cool#method_Str> on all of the above produces the I<short> version of the information,
+The C<Str> method on all of the above produces the I<short> version of the information,
 at the current time the C<name>.
 
 All the objects have other methods that can be useful when trying to identify the