Add docs and release notes for datetime_filters tag library.

docs/source/ref/templatetags.rst

@@ -124,3 +124,23 @@ Argument             Description
 ``basket``           The basket instance to calculate shipping charges for
 ``name``             The variable name to assign the charge to
 ===================  =====================================================
+
+Datetime filters
+-------------
+
+Load these tags using ``{% load datetime_filters %}``.
+
+``timedelta``
+~~~~~~~~~~~~~~~~~
+
+Returns a human-readable string representation of a time delta, in the current locale:
+
+.. code-block:: html+django
+
+    Time since creation: {{ basket.time_since_creation|timedelta }}
+
+This renders something like:
+
+.. code-block:: html
+
+    Time since creation: 2 days

docs/source/releases/v2.0.rst

@@ -129,6 +129,9 @@ Minor changes
   and the logic in ``ProductReviewList`` adjusted so that the form fields
   don't have to be rendered manually because of form errors.
 
+- Added a ``datetime_filters`` tag library that provides a ``timedelta`` template
+  filter for rendering time deltas in human readable format.
+
 Dependency changes
 ------------------