typo fix

Co-authored-by: Kurt McKee <contactme@kurtmckee.org>

Author: danthedeckie

test_simpleeval.py

@@ -1364,7 +1364,7 @@ class Foo:
             def bar(self):
                 yield "Hello, world!"
 
-        # Test the genertor does work - also adds the `yield` to codecov...
+        # Test the generator does work - also adds the `yield` to codecov...
         assert list(Foo().bar()) == ["Hello, world!"]
 
         evil = "foo.bar().gi_frame.f_globals['__builtins__'].exec('raise RuntimeError(\"Oh no\")')"