generate new message details page and fix logic for injecting {%raw} tags only when making messages…

pkg/polymer/tool/create_message_details_page.dart

Index: pkg/polymer/tool/create_message_details_page.dart
diff --git a/pkg/polymer/tool/create_message_details_page.dart b/pkg/polymer/tool/create_message_details_page.dart
index 0e178cd24f74a6c153fc8236496d83386bb69b12..c1e25663939de92cd8ef27631e625cda2898cc2c 100644
--- a/pkg/polymer/tool/create_message_details_page.dart
+++ b/pkg/polymer/tool/create_message_details_page.dart
@@ -81,10 +81,11 @@ _getMessagesFrom(Symbol libName, Map seen, List templates) {
 _generateMessage(MessageTemplate template, bool forSite, StringBuffer sb) {
   var details = template.details == null
       ? 'No details available' : template.details;
+  if (forSite) details = '{% raw %}$details{% endraw %}';
   var id = template.id;
   var hashTag = '${id.package}_${id.id}';
   var title = '### ${template.description} [#${id.id}](#$hashTag)';
-  var body = '\n{% raw %}$details{% endraw %}\n\n----\n\n';
+  var body = '\n$details\n\n----\n\n';
   // We add the anchor inside the <h3> title, otherwise the link doesn't work.
   if (forSite) {
     sb..write(title)