Fixed wrong example

Such an obvious mistake.

Author: ZzZombo

doc/Type/Str.pod6

@@ -1007,7 +1007,7 @@ for repeated operations:
 
     my $string = "A character in the 'Flintstones' is: barney";
     $string ~~ /(barney)/;
-    my $ref := substr-rw($string, $0.from, $0.to);
+    my $ref := substr-rw($string, $0.from, $0.to-$0.from);
     $string.say;
     # OUTPUT: «A character in the 'Flintstones' is: barney␤»
     $ref = "fred";
@@ -1017,11 +1017,6 @@ for repeated operations:
     $string.say;
     # OUTPUT: «A character in the 'Flintstones' is: wilma␤»
 
-Notice that the start position and length of string to replace has been
-specified via the C<.from> and C<.to> methods on the C<Match> object, C<$0>.
-It is thus not necessary to count characters in order to replace a
-substring, hence making the code more flexible.
-
 =head2 routine samemark
 
     multi sub samemark(Str:D $string, Str:D $pattern --> Str:D)