[4.2.x] Refs #34140 -- Applied rst code-block to non-Python examples.

Thanks to J.V. Zammit, Paolo Melchiorre, and Mariusz Felisiak for
reviews.

Backport of 534ac48297 from main.

docs/ref/contrib/admin/index.txt

@@ -3236,7 +3236,9 @@ with an instance namespace corresponding to the name of the Site instance.
 
 So - if you wanted to get a reference to the Change view for a particular
 ``Choice`` object (from the polls application) in the default admin, you would
-call::
+call:
+
+.. code-block:: pycon
 
     >>> from django.urls import reverse
     >>> c = Choice.objects.get(...)
@@ -3249,7 +3251,9 @@ This will find the first registered instance of the admin application
 If you want to find a URL in a specific admin instance, provide the name of
 that instance as a ``current_app`` hint to the reverse call. For example,
 if you specifically wanted the admin view from the admin instance named
-``custom``, you would need to call::
+``custom``, you would need to call:
+
+.. code-block:: pycon
 
     >>> change_url = reverse('admin:polls_choice_change', args=(c.id,), current_app='custom')