FAQ: Protocol buffers are now supported. Update the entry.

R=rsc, adg
CC=golang-dev
https://golang.org/cl/702042

doc/go_faq.html

@@ -152,10 +152,10 @@ to C++ libraries.  There is no safe way to call Go code from C or C++ yet.
 Does Go support Google's protocol buffers?</h3>
 
 <p>
-Protocol buffers are supported.  We plan to have the next release of the
-protocol buffer source code include Go code generators
-and a Go library for them. The implementation uses data reflection
-at run time so it is slow, but a new implementation is planned.
+A separate open source project provides the necessary compiler plugin and library.
+It is available at
+<a href="http://code.google.com/p/goprotobuf/">http://code.google.com/p/goprotobuf/</a>
+</p>
 
 <h3 id="Can_I_translate_the_Go_home_page">
 Can I translate the Go home page into another language?</h3>