Fix typo

Author: dabeaz

Notes/03_Program_organization/05_Main_module.md

@@ -256,7 +256,7 @@ if __name__ == '__main__':
 
 In the file `report.py` add a `main()` function that accepts a list of
 command line options and produces the same output as before.  You
-should be able to run it interatively like this:
+should be able to run it interactively like this:
 
 ```python
 >>> import report