Fix syntax highlighting in form descriptions

www/common/common-ui-elements.js

@@ -1069,6 +1069,7 @@ define([
             editor.replaceSelections(newTexts, 'around');
             editor.focus();
         };
+        Messages.mdToolbar_embed = "Embed file"; // XXX
         for (var k in actions) {
             $('<button>', {
                 'data-type': k,

www/form/inner.js

@@ -27,7 +27,7 @@ define([
     '/bower_components/sortablejs/Sortable.min.js',
 
     'cm/addon/display/placeholder',
-    'cm/mode/markdown/markdown',
+    'cm/mode/gfm/gfm',
     'css!cm/lib/codemirror.css',
 
     'css!/bower_components/codemirror/lib/codemirror.css',