Fix links fo operators 'ff' and 'fff'.

Rewording of the explaination within the range operators about
flip-flop operators in Perl 5 compared to ff and fff in Perl 6.

Author: fluca1978

doc/Language/5to6-perlop.pod6

@@ -176,10 +176,10 @@ The following example shows the effects of all the above range operators
 (^5).list;     # (0 1 2 3 4)
 =end code
 
-In scalar context, C<..> and C<...> work as flip-flop operators in Perl
-5, but are little-known, and probably even less used. Those operations
-have been taken over by C<ff> and C<fff> in Perl 6, but are not clearly
-documented at this time.
+In Perl 5, in scalar context, the operators C<..> and C<...> work
+as flip-flop operators, even if they are little-known and probably
+less used. Those oeprators have been replaced in Perl 6
+by L<ff|/routine/ff> and L<fff|/routine/fff> respectively.
 
 =head2 Conditional Operator