#22170: avoid printing newlines twice in tutorial example.

Doc/tutorial/classes.rst

@@ -802,7 +802,7 @@ using a :keyword:`for` statement::
    for char in "123":
        print(char)
    for line in open("myfile.txt"):
-       print(line)
+       print(line, end='')
 
 This style of access is clear, concise, and convenient.  The use of iterators
 pervades and unifies Python.  Behind the scenes, the :keyword:`for` statement