Typo fix in test

Author: henryiii

tests/test_iostream.py

@@ -30,7 +30,7 @@ def test_multi_captured(capture):
 
 
 # capfd seems to be unstable on pypy
-@pytest.unsuppported_on_pypy
+@pytest.unsupported_on_pypy
 def test_successful(capfd):
     m.raw_output("I've been output to cout, I hope!")
     stdout, stderr = capfd.readouterr()