Docs shouldn't recommend `mod_rewrite` for Apache

[LiberalArtist]

The documentation on using Apache with the Racket Web Server currently recommends mod_rewrite:

web-server/web-server-doc/web-server/scribblings/server-faq.scrbl

Lines 7 to 29 in e321f84

	@section{How do I use Apache with the Racket Web Server?}
	You may want to put Apache in front of your Racket Web Server
	application. Apache can rewrite and proxy requests for a private (or
	public) Racket Web Server:
	@verbatim{
	RewriteEngine on
	RewriteRule ^(.*)$ http://localhost:8080/$1 [P,NE]
	}
	The first argument to @exec{RewriteRule} is a match pattern. The second
	is how to rewrite the URL. The bracketed part contains flags that
	specify the type of rewrite, in this case the @litchar{P} flag instructs
	Apache to proxy the request. (If you do not include this, Apache will
	return an HTTP Redirect response and the client will make a second
	request to @litchar{localhost:8080} which will not work on a different
	machine.) In addition, the @litchar{NE} flag is needed to avoid
	escaping parts of the URL --- without it, a @litchar{;} is escaped as
	@litchar{%3B} which will break the proxied request.
	See Apache's documentation for more details on
	@link["http://httpd.apache.org/docs/current/mod/mod_rewrite.html#rewriterule"]{RewriteRule}.

However, the extended documentation for mod_rewrite lists Simple Proxying as an example of when not to use mod_rewrite: it recommends ProxyPass from mod_proxy.

I was reminded of this while writing #126 (comment). I'm not sure if I have a working example to contribute at the moment (I'm in the midst of some configuration changes locally), but I'll send one if I do.