fix compilation issues

Author: coke

doc/Language/contexts.pod6

@@ -65,11 +65,12 @@ In the case of I<listy> things, the numeric value will be in general equivalent
 
 In a I<string context>, values can be manipulated as strings. This context is used, for instance, for printing values to standard output.
 
+=for code :preamble<my $very-complicated-and-hairy-object>
     say $very-complicated-and-hairy-object; # OUTPUT: something meaningful
 
 Or when smart-matching to a regular expression:
 
-    p6: say 333444777 ~~ /(3+)/; # OUTPUT: «｢333｣␤ 0 => ｢333｣␤»
+    say 333444777 ~~ /(3+)/; # OUTPUT: «｢333｣␤ 0 => ｢333｣␤»
 
 In general, the L<C<Str> routine|/routine/Str> will be called on a variable to contextualize it; since this method is inherited from L<Mu>, it is always present, but it is not always guaranteed to work. In some core classes it will issue a warning.