migrate snippets:show to static bundle

app/assets/javascripts/dispatcher.js

@@ -294,11 +294,6 @@ var Dispatcher;
             .then(callDefault)
             .catch(fail);
           break;
-        case 'snippets:show':
-          import('./pages/snippets/show')
-            .then(callDefault)
-            .catch(fail);
-          break;
         case 'import:fogbugz:new_user_map':
           import('./pages/import/fogbugz/new_user_map')
             .then(callDefault)

app/assets/javascripts/pages/snippets/show/index.js

-/* eslint-disable no-new */
 import LineHighlighter from '../../../line_highlighter';
 import BlobViewer from '../../../blob/viewer';
 import ZenMode from '../../../zen_mode';
 import initNotes from '../../../init_notes';
 
-export default () => {
-  new LineHighlighter();
-  new BlobViewer();
+document.addEventListener('DOMContentLoaded', () => {
+  new LineHighlighter(); // eslint-disable-line no-new
+  new BlobViewer(); // eslint-disable-line no-new
   initNotes();
-  new ZenMode();
-};
+  new ZenMode(); // eslint-disable-line no-new
+});