Correctly render the date filter widgets with their own context

hypha/apply/projects/templates/application_projects/filters/widgets/date_range_input_widget.html

-{% include widget.subwidgets.0.template_name %}
-<span>to:</span>
-{% include widget.subwidgets.1.template_name %}
+{% for widget in widget.subwidgets %}
+    {% include widget.template_name %}
+    {% if forloop.last %}
+        <span>to:</span>
+    {% endif %}
+{% endfor %}