Fixed misspelled remark in comments.

rest_framework/tests/generics.py

@@ -344,7 +344,7 @@ class ExampleView(generics.ListCreateAPIView):
 class TestM2MBrowseableAPI(TestCase):
     def test_m2m_in_browseable_api(self):
         """
-        Test for particularly ugly reression with m2m in browseable API
+        Test for particularly ugly regression with m2m in browseable API
         """
         request = factory.get('/', HTTP_ACCEPT='text/html')
         view = ExampleView().as_view()