Fixed Sphinx highlight warnings in docs.

docs/topics/i18n/translation.txt

@@ -70,8 +70,6 @@ as a shorter alias, ``_``, to save typing.
        global ``_()`` function causes interference. Explicitly importing
        ``ugettext()`` as ``_()`` avoids this problem.
 
-.. highlightlang:: python
-
 In this example, the text ``"Welcome to my site."`` is marked as a translation
 string::
 
@@ -1209,6 +1207,8 @@ Additionally, if there are complex rules around pluralization, the catalog view
 will render a conditional expression. This will evaluate to either a ``true``
 (should pluralize) or ``false`` (should **not** pluralize) value.
 
+.. highlight:: python
+
 The ``json_catalog`` view
 -------------------------
 
@@ -1243,7 +1243,8 @@ The view is hooked up to your application and configured in the same fashion as
 
 The response format is as follows:
 
-.. code-block:: json
+.. code-block:: text
+..   JSON doesn't allow comments so highlighting as JSON won't work here.
 
     {
         "catalog": {
@@ -1266,9 +1267,7 @@ Server-side caching will reduce CPU load. It's easily implemented with the
 :func:`~django.views.decorators.cache.cache_page` decorator. To trigger cache
 invalidation when your translations change, provide a version-dependent key
 prefix, as shown in the example below, or map the view at a version-dependent
-URL.
-
-.. code-block:: python
+URL::
 
     from django.views.decorators.cache import cache_page
     from django.views.i18n import javascript_catalog
@@ -1282,9 +1281,7 @@ Client-side caching will save bandwidth and make your site load faster. If
 you're using ETags (:setting:`USE_ETAGS = True <USE_ETAGS>`), you're already
 covered. Otherwise, you can apply :ref:`conditional decorators
 <conditional-decorators>`. In the following example, the cache is invalidated
-whenever you restart your application server.
-
-.. code-block:: python
+whenever you restart your application server::
 
     from django.utils import timezone
     from django.views.decorators.http import last_modified
@@ -1360,8 +1357,8 @@ After defining these URL patterns, Django will automatically add the
 language prefix to the URL patterns that were added by the ``i18n_patterns``
 function. Example::
 
-    from django.urls import reverse
-    from django.utils.translation import activate
+    >>> from django.urls import reverse
+    >>> from django.utils.translation import activate
 
     >>> activate('en')
     >>> reverse('sitemap-xml')
@@ -1417,8 +1414,8 @@ URL patterns can also be marked translatable using the
 After you've created the translations, the :func:`~django.urls.reverse`
 function will return the URL in the active language. Example::
 
-    from django.urls import reverse
-    from django.utils.translation import activate
+    >>> from django.urls import reverse
+    >>> from django.utils.translation import activate
 
     >>> activate('en')
     >>> reverse('news:category', kwargs={'slug': 'recent'})
@@ -1716,8 +1713,6 @@ translation utilities with a ``gettext`` package if the command ``xgettext
 Customizing the ``makemessages`` command
 ----------------------------------------
 
-.. highlightlang:: python
-
 If you want to pass additional parameters to ``xgettext``, you need to create a
 custom :djadmin:`makemessages` command and override its ``xgettext_options``
 attribute::
@@ -1756,8 +1751,6 @@ Miscellaneous
 The ``set_language`` redirect view
 ----------------------------------
 
-.. highlightlang:: python
-
 .. currentmodule:: django.views.i18n
 
 .. function:: set_language(request)

docs/topics/security.txt

@@ -29,7 +29,8 @@ which are particularly dangerous to HTML. While this protects users from most
 malicious input, it is not entirely foolproof. For example, it will not
 protect the following:
 
-.. code-block:: html+django
+.. code-block:: text
+..   highlighting as html+django fails due to intentionally missing quotes.
 
     <style class={{ var }}>...</style>