Fixed some ReST errors regarding backticks

docs/ref/contrib/admin/actions.txt

@@ -269,8 +269,8 @@ Making actions available site-wide
 
         admin.site.add_action(export_selected_objects)
 
-    This makes the `export_selected_objects` action globally available as an
-    action named `"export_selected_objects"`. You can explicitly give the action
+    This makes the ``export_selected_objects`` action globally available as an
+    action named "export_selected_objects". You can explicitly give the action
     a name -- good if you later want to programmatically :ref:`remove the action
     <disabling-admin-actions>` -- by passing a second argument to
     :meth:`AdminSite.add_action()`::

docs/ref/contrib/admin/admindocs.txt

@@ -156,6 +156,6 @@ Edit this object
 Using these bookmarklets requires that you are either logged into the
 :mod:`Django admin <django.contrib.admin>` as a
 :class:`~django.contrib.auth.models.User` with
-:attr:`~django.contrib.auth.models.User.is_staff` set to `True`, or that the
+:attr:`~django.contrib.auth.models.User.is_staff` set to ``True``, or that the
 ``XViewMiddleware`` is installed and you are accessing the site from an IP
 address listed in :setting:`INTERNAL_IPS`.

docs/ref/models/querysets.txt

@@ -913,7 +913,7 @@ needed by ``select_related``), it is able to detect that the ``best_pizza``
 objects have already been fetched, and it will skip fetching them again.
 
 Chaining ``prefetch_related`` calls will accumulate the lookups that are
-prefetched. To clear any ``prefetch_related`` behavior, pass `None` as a
+prefetched. To clear any ``prefetch_related`` behavior, pass ``None`` as a
 parameter::
 
    >>> non_prefetched = qs.prefetch_related(None)