Minor style.9 edit: remove reference to how to format K&R code

[Warner Losh]

We've not added new code with K&R formatting for quite some time. In fact,
we're actively removing it when appropriate.

https://reviews.freebsd.org/D14051

Removes the text on how to format it. I haven't added a 'don't use K&R
style' because nobody is doing that, so we should continue to rely on
people's good judgement here. K&R was obsoleted in 1990 and hasn't been
relevant for new platforms since maybe 1995. Old code that was shared with
other projects basically ending around 2000 or so. If this were as late as
maybe 2005 and I was doing this, I'd add a statement, but we're more than a
decade past even that late date for relevance.

So, let's do this the same way as before: add yourself to the review, click
yes or no. If you click no, please explain why. If there's no opposition,
I'll push this into the tree. If there's opposition that articulates a
compelling reason I won't.

Warner