Refactoring doctests (#5518)

Refactoring doctests

src/_pytest/doctest.py

@@ -364,10 +364,7 @@ def _patch_unwrap_mock_aware():
     contextmanager which replaces ``inspect.unwrap`` with a version
     that's aware of mock objects and doesn't recurse on them
     """
-    real_unwrap = getattr(inspect, "unwrap", None)
-    if real_unwrap is None:
-        yield
-    else:
+    real_unwrap = inspect.unwrap
 
     def _mock_aware_unwrap(obj, stop=None):
         try: