Update comment

Author: tomasr8

Lib/test/test_capi/test_opt.py

@@ -2034,8 +2034,8 @@ def test_call_isinstance_tuple_of_classes(self):
         def testfunc(n):
             x = 0
             for _ in range(n):
-                # The optimization currently only narrows to bool
-                # when the second argument is a tuple of classes.
+                # A tuple of classes is currently not optimized,
+                # so this is only narrowed to bool:
                 y = isinstance(42, (int, str))
                 if y:
                     x += 1