Fix more raise statments in the docs.

Doc/tutorial/controlflow.rst

@@ -329,7 +329,8 @@ defined to allow.  For example::
            if ok in ('y', 'ye', 'yes'): return True
            if ok in ('n', 'no', 'nop', 'nope'): return False
            retries = retries - 1
-           if retries < 0: raise IOError, 'refusenik user'
+           if retries < 0:
+               raise IOError('refusenik user')
            print(complaint)
 
 This function can be called either like this: ``ask_ok('Do you really want to

Doc/tutorial/errors.rst

@@ -262,7 +262,7 @@ directly or indirectly.  For example::
    ...     print('My exception occurred, value:', e.value)
    ... 
    My exception occurred, value: 4
-   >>> raise MyError, 'oops!'
+   >>> raise MyError('oops!')
    Traceback (most recent call last):
      File "<stdin>", line 1, in ?
    __main__.MyError: 'oops!'