Fixed #25670 -- Allowed dictsort to sort a list of lists.

Thanks Tim Graham for the review.

docs/ref/templates/builtins.txt

@@ -1443,6 +1443,40 @@ then the output would be::
     * 1984 (George)
     * Timequake (Kurt)
 
+``dictsort`` can also order a list of lists (or any other object implementing
+``__getitem__()``) by elements at specified index. For example::
+
+    {{ value|dictsort:0 }}
+
+If ``value`` is:
+
+.. code-block:: python
+
+    [
+        ('a', '42'),
+        ('c', 'string'),
+        ('b', 'foo'),
+    ]
+
+then the output would be:
+
+.. code-block:: python
+
+    [
+        ('a', '42'),
+        ('b', 'foo'),
+        ('c', 'string'),
+    ]
+
+You must pass the index as an integer rather than a string. The following
+produce empty output::
+
+    {{ values|dictsort:"0" }}
+
+.. versionchanged:: 1.10
+
+    The ability to order a list of lists was added.
+
 .. templatefilter:: dictsortreversed
 
 ``dictsortreversed``

docs/releases/1.10.txt

@@ -333,6 +333,9 @@ Templates
 
 * Added the ``is`` comparison operator to the :ttag:`if` tag.
 
+* Allowed :tfilter:`dictsort` to order a list of lists by an element at a
+  specified index.
+
 Tests
 ~~~~~