Specify translation context, so the value can be easily changed in a … (#4012)

Specify translation context, so the value can be easily changed in a project if needed.

src/oscar/apps/catalogue/abstract_models.py

 from django.utils.safestring import mark_safe
 from django.utils.translation import get_language
 from django.utils.translation import gettext_lazy as _
-from django.utils.translation import pgettext_lazy
+from django.utils.translation import pgettext, pgettext_lazy
 from treebeard.mp_tree import MP_Node
 
 from oscar.core.loading import get_class, get_classes, get_model
     @property
     def _boolean_as_text(self):
         if self.value:
-            return _("Yes")
-        return _("No")
+            return pgettext("Product attribute value", "Yes")
+        return pgettext("Product attribute value", "No")
 
     @property
     def value_as_html(self):

tests/integration/catalogue/test_attributes.py

         assert attr_val.value_as_text == "No"
 
 
-
 class TestMultiOptionAttributes(TestCase):
 
     def setUp(self):