assign widgets shim as attribute on html shim

needed to keep both `from IPython.html import widgets`
and `from IPython.html.widgets import Widget`
working

IPython/html.py

@@ -1,24 +1,28 b''
 """
 Shim to maintain backwards compatibility with old IPython.html imports.
 """
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import sys
 from warnings import warn
 
 warn("The `IPython.html` package has been deprecated. "
      "You should import from `jupyter_notebook` instead. "
      "`IPython.html.widgets` has moved to `ipython_widgets`.")
 
 from IPython.utils.shimmodule import ShimModule
 
-sys.modules['IPython.html.widgets'] = ShimModule(
+_widgets = sys.modules['IPython.html.widgets'] = ShimModule(
     src='IPython.html.widgets', mirror='ipython_widgets')
 
-sys.modules['IPython.html'] = ShimModule(
+_html = ShimModule(
     src='IPython.html', mirror='jupyter_notebook')
 
+# hook up widgets
+_html.widgets = _widgets
+sys.modules['IPython.html'] = _html
+
 if __name__ == '__main__':
     from jupyter_notebook import notebookapp as app
     app.launch_new_instance()