> 1. On the howto/unicode.html
> 2. Somewhere in the stdtypes.html#typesseq description (maybe with other notes at the bottom)
> 3. As a note to the stdtypes.html#str.splitlines method description (where it is in the previous patch.)

(3) is the best place. For Python 2, you should add a new unicode.splitlines entry, whereas the str.splitlines should be updated in Python 3.

> I can do this for 2.7, 3.2 and 3.3 separately.

You don't have to do it for 3.3: 2.7 and 3.2 are enough (I will do the change in 3.3 using Mercurial).