Coding system of %doc file

[Laurent Rineau <laurent rineau__fedora_extras normalesup org>]

Some usual doc files, like AUTHORS, use accented characters. The packaging 
guidelines do not tell anything about the coding of those files. rpmlint used 
to signal non-utf-8 files, but my version rpmlint-0.78-2.fc5 no longer do.

Is there a policy?