Changed the repr of NOT_USED to pytest_cases.NOT_USED

Author: Sylvain MARIE

pytest_cases/main_fixtures.py

@@ -477,7 +477,7 @@ def wrapped_fixture_func(*args, **kwargs):
 
 class _NotUsed:
     def __repr__(self):
-        return "<not_used>"
+        return "pytest_cases.NOT_USED"
 
 
 NOT_USED = _NotUsed()