Update URL routing examples in usage guide. (#1339)

docs/guide/usage.txt

@@ -271,7 +271,7 @@ The URL conf
 
 We need a URL pattern to call the view::
 
-    url(r'^list$', views.product_list)
+    path('list/', views.product_list, name="product-list")
 
 
 The template
@@ -305,12 +305,12 @@ You must provide either a ``model`` or ``filterset_class`` argument, similar to
 ``ListView`` in Django itself::
 
     # urls.py
-    from django.conf.urls import url
+    from django.urls import path
     from django_filters.views import FilterView
     from myapp.models import Product
 
     urlpatterns = [
-        url(r'^list/$', FilterView.as_view(model=Product)),
+        path("list/", FilterView.as_view(model=Product), name="product-list"),
     ]
 
 If you provide a ``model`` optionally you can set ``filterset_fields`` to specify a list or a tuple of
@@ -326,12 +326,12 @@ its use is deprecated.  It can be found at
 to it as the class based view::
 
     # urls.py
-    from django.conf.urls import url
+    from django.urls import path
     from django_filters.views import object_filter
     from myapp.models import Product
 
     urlpatterns = [
-        url(r'^list/$', object_filter, {'model': Product}),
+        path("list/', object_filter, {'model': Product}, name="product-list),
     ]
 
 The needed template and its context variables will also be the same as the