Confirm that the prime example is actually correct. We get so many complaints about a "buggy example" on docs@python, let us hope this cuts them in half at least.

birkenfeld · birkenfeld · commit bdbdfb197837 · 2011-08-08T21:45:13.000+02:00
diff --git a/Doc/tutorial/controlflow.rst b/Doc/tutorial/controlflow.rst
@@ -184,6 +184,9 @@ following loop, which searches for prime numbers::
    8 equals 2 * 4
    9 equals 3 * 3
 
+(Yes, this is the correct code.  Look closely: the ``else`` clause belongs to
+the :keyword:`for` loop, **not** the :keyword:`if` statement.)
+
 
 .. _tut-pass:
 
