fix formatting code

doc/Language/hashmap.pod6

@@ -136,7 +136,7 @@ names must be quoted. For example, using the common L<Pair|/type/Pair> syntax:
     say %h.values.sort.raku      # OUTPUT: «(2, 3, "a").Seq␤»
 
 The stringification of the keys can lead to surprising results. For example, the Raku
-module C<CSV::Parser> in one mode returns a CSV data line as a hash of C<{UInt => 'value'}> pairs
+module C<CSV::Parser> in one mode returns a CSV data line as a hash of C«{UInt => 'value'}» pairs
 which can look like this fragment of a 20-field line:
 
     my %csv = '2' => 'a', '10' => 'b';