Fix whitespace handling in examples

doc/Language/typesystem.pod6

@@ -803,14 +803,15 @@ objects:
 
 For example, in file C<config> we have:
 
-C<a 1
-b 2>
+=for code :lang<text>
+a 1
+b 2
 
 We can create an enum using it with this code:
 
-    =for code :skip-test<needs filesystem>
-    enum ConfigValues ('config'.IO.lines.map({ my ($key, $value) = $_.words; $key => $value }));
-    say ConfigValues.enums;          # OUTPUT: «Map.new((a => 1, b => 2))␤»
+=for code :skip-test<needs filesystem>
+enum ConfigValues ('config'.IO.lines.map({ my ($key, $value) = $_.words; $key => $value }));
+say ConfigValues.enums;          # OUTPUT: «Map.new((a => 1, b => 2))␤»
 
 Firstly, we read lines from C<config> file, split every line using
 C<words> method and return resulting pair for every line, thus