Enable codemirror search/replace shortcuts

IPython/html/static/texteditor/js/editor.js

@@ -6,6 +6,7 b' define(['
     'base/js/utils',
     'codemirror/lib/codemirror',
     'codemirror/mode/meta',
+    'codemirror/addon/search/search'
     ],
 function($,
     utils,

IPython/html/templates/texteditor.html

@@ -4,6 +4,7 b''
 
 {% block stylesheet %}
 <link rel="stylesheet" href="{{ static_url('components/codemirror/lib/codemirror.css') }}">
+<link rel="stylesheet" href="{{ static_url('components/codemirror/addon/dialog/dialog.css') }}">
 
 {{super()}}
 {% endblock %}