Bring the YAML package's style up to modern standards.

pkg/yaml/README.md

Index: pkg/yaml/README.md
diff --git a/pkg/yaml/README.md b/pkg/yaml/README.md
index 47a5419fa75a56cc1951b2513129af53eeea25d1..531162f417bea3e3ea049d1161ca84bb682db115 100644
--- a/pkg/yaml/README.md
+++ b/pkg/yaml/README.md
@@ -3,21 +3,27 @@ A parser for [YAML](http://www.yaml.org/).
 Use `loadYaml` to load a single document, or `loadYamlStream` to load a
 stream of documents. For example:
 
-    import 'package:yaml/yaml.dart';
-    main() {
-      var doc = loadYaml("YAML: YAML Ain't Markup Language");
-      print(doc['YAML']);
-    }
+```dart
+import 'package:yaml/yaml.dart';
+
+main() {
+  var doc = loadYaml("YAML: YAML Ain't Markup Language");
+  print(doc['YAML']);
+}
+```
 
 This library currently doesn't support dumping to YAML. You should use
 `JSON.encode` from `dart:convert` instead:
 
-    import 'dart:convert';
-    import 'package:yaml/yaml.dart';
-    main() {
-      var doc = loadYaml("YAML: YAML Ain't Markup Language");
-      print(JSON.encode(doc));
-    }
+```dart
+import 'dart:convert';
+import 'package:yaml/yaml.dart';
+
+main() {
+  var doc = loadYaml("YAML: YAML Ain't Markup Language");
+  print(JSON.encode(doc));
+}
+```
 
 The source code for this package is at <http://code.google.com/p/dart>.
 Please file issues at <http://dartbug.com>. Other questions or comments can be