[1.7.x] Fixed #21941 -- Documented the kwargs param of django.conf.urls.url().

Thanks cjerdonek for the report.

Backport of a7797577 from master

docs/ref/urls.txt

@@ -76,6 +76,9 @@ This function takes five arguments, most of which are optional::
 
     url(regex, view, kwargs=None, name=None, prefix='')
 
+The ``kwargs`` parameter allows you to pass additional arguments to the view
+function or method. See :ref:`views-extra-options` for an example.
+
 See :ref:`Naming URL patterns <naming-url-patterns>` for why the ``name``
 parameter is useful.
 

docs/topics/http/urls.txt

@@ -51,11 +51,17 @@ algorithm the system follows to determine which Python code to execute:
 3. Django runs through each URL pattern, in order, and stops at the first
    one that matches the requested URL.
 
-4. Once one of the regexes matches, Django imports and calls the given
-   view, which is a simple Python function (or a :doc:`class based view
-   </topics/class-based-views/index>`). The view gets passed an
-   :class:`~django.http.HttpRequest` as its first argument and any values
-   captured in the regex as remaining arguments.
+4. Once one of the regexes matches, Django imports and calls the given view,
+   which is a simple Python function (or a :doc:`class based view
+   </topics/class-based-views/index>`). The view gets passed the following
+   arguments:
+
+   * An instance of :class:`~django.http.HttpRequest`.
+   * If the matched regular expression returned no named groups, then the
+     matches from the regular expression are provided as positional arguments.
+   * The keyword arguments are made up of any named groups matched by the
+     regular expression, overridden by any arguments specified in the optional
+     ``kwargs`` argument to :func:`django.conf.urls.url`.
 
 5. If no regex matches, or if an exception is raised during any
    point in this process, Django invokes an appropriate