correct example to unit module

Author: stmuk

lib/Language/5to6.pod

@@ -1134,7 +1134,7 @@ C<is export> role on the relevant subs and I<all> subs with this role are
 then exported.  Hence, the following module C<Bar> exports the subs C<foo>
 and C<bar> but not C<baz>:
 
-    module Bar;
+    unit module Bar;
 
     sub foo($a) is export { say "foo $a" }
     sub bar($b) is export { say "bar $b" }