[4.1.x] Fixed #34180 -- Added note about resetting language in test tear-downs.

Co-authored-by: Faris Naimi <farisfaris66@gmail.com>

Backport of 40217d1a82b0c16cddba377325d12b2c253f402a from main

AUTHORS

@@ -326,6 +326,7 @@ answer newbie questions, and generally made Django that much better:
     Florian Apolloner <florian@apolloner.eu>
     Florian Demmer <fdemmer@gmail.com>
     Florian Moussous <florian.moussous@gmail.com>
+    fnaimi66 <https://github.com/fnaimi66>
     Fran Hrženjak <fran.hrzenjak@gmail.com>
     Francisco Albarran Cristobal <pahko.xd@gmail.com>
     Francisco Couzo <franciscouzo@gmail.com>

docs/topics/testing/tools.txt

@@ -638,6 +638,14 @@ or by including the ``Accept-Language`` HTTP header in the request::
         response = self.client.get('/', HTTP_ACCEPT_LANGUAGE='fr')
         self.assertEqual(response.content, b"Bienvenue sur mon site.")
 
+.. note::
+
+    When using these methods, ensure to reset the active language at the end of
+    each test::
+
+        def tearDown(self):
+            translation.activate(settings.LANGUAGE_CODE)
+
 More details are in :ref:`how-django-discovers-language-preference`.
 
 If the middleware isn't enabled, the active language may be set using