Fix the output of built-in iter() function example in Iterators (Sect…

…ion 9.8) of The Python Tutorial (GH-30110)

Updated the output for it=iter(s) from <iterator object at 0x00A1DB50> to <str_iterator object at 0x10c90e650>

Doc/tutorial/classes.rst

@@ -797,7 +797,7 @@ using the :func:`next` built-in function; this example shows how it all works::
    >>> s = 'abc'
    >>> it = iter(s)
    >>> it
-   <iterator object at 0x00A1DB50>
+   <str_iterator object at 0x10c90e650>
    >>> next(it)
    'a'
    >>> next(it)