Make the widget warning easier to catch by specifying the module.

IPython/html/widgets/__init__.py

@@ -1,32 +1,38 b''
 from .widget import Widget, DOMWidget, CallbackDispatcher, register
 
 from .widget_bool import Checkbox, ToggleButton
 from .widget_button import Button
 from .widget_box import Box, Popup, FlexBox, HBox, VBox
 from .widget_float import FloatText, BoundedFloatText, FloatSlider, FloatProgress, FloatRangeSlider
 from .widget_image import Image
 from .widget_int import IntText, BoundedIntText, IntSlider, IntProgress, IntRangeSlider
 from .widget_output import Output
 from .widget_selection import RadioButtons, ToggleButtons, Dropdown, Select
 from .widget_selectioncontainer import Tab, Accordion
 from .widget_string import HTML, Latex, Text, Textarea
 from .interaction import interact, interactive, fixed, interact_manual
 from .widget_link import Link, link, DirectionalLink, dlink
 
 # Deprecated classes
 from .widget_bool import CheckboxWidget, ToggleButtonWidget
 from .widget_button import ButtonWidget
 from .widget_box import ContainerWidget, PopupWidget
 from .widget_float import FloatTextWidget, BoundedFloatTextWidget, FloatSliderWidget, FloatProgressWidget
 from .widget_image import ImageWidget
 from .widget_int import IntTextWidget, BoundedIntTextWidget, IntSliderWidget, IntProgressWidget
 from .widget_selection import RadioButtonsWidget, ToggleButtonsWidget, DropdownWidget, SelectWidget
 from .widget_selectioncontainer import TabWidget, AccordionWidget
 from .widget_string import HTMLWidget, LatexWidget, TextWidget, TextareaWidget
 
-# we use warn_explicit so we have very brief messages without file or line numbers
-# the concern is that file or line numbers will confuse the interactive user
+# We use warn_explicit so we have very brief messages without file or line numbers.
+# The concern is that file or line numbers will confuse the interactive user.
+# To ignore this warning, do:
+#
+#     from warnings import filterwarnings
+#     filterwarnings('ignore', module='IPython.html.widgets')
+
 from warnings import warn_explicit
 __warningregistry__ = {}
 warn_explicit("IPython widgets are experimental and may change in the future.",
-              FutureWarning, '', 0, registry=__warningregistry__)
+              FutureWarning, '', 0, module = 'IPython.html.widgets',
+              registry = __warningregistry__, module_globals = globals)