docs/154494: rcorder(8) not quite accurate

[Gavin Atkinson]

On Mon, 6 Jun 2011, Doug Barton wrote:
> I wish that you had discussed this with freebsd-rc@ before committing. :-/  I
> can't see any good thing that comes from documenting this. OTOH, the benefit
> of not documenting it is that eventually we can remove support for the
> un-documented versions because they are no longer used.

I must admit that I was a little surprised to see the man page be so 
explicit in saying that no other keywords were accepted, and yet the 
rcorder(8) code accepts them happily.  

I wasn't happy with the patch submitted in the PR for a number of reasons, 
but I felt that my rewording made it clear that these were accepted only 
historically, and therefore not suggested for use in new scripts.  I tried 
to get the balance correct between documenting behaviour, and discouraging 
the use of deprecated features.

I'm happy to revert this if you think these should remain deliberately 
undocumented.

Gavin