doc: delete faq question about 6g

Fixes #3230.

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/5753071

doc/go_faq.html

@@ -76,20 +76,6 @@ The logo and mascot are covered by the
 license.
 </p>
 
-<h3 id="What_kind_of_a_name_is_6g">
-What kind of a name is 6g?</h3>
-
-<p>
-The <code>6g</code> (and <code>8g</code> and <code>5g</code>) compiler is named in the
-tradition of the Plan 9 C compilers, described in
-<a href="http://plan9.bell-labs.com/sys/doc/compiler.html">
-http://plan9.bell-labs.com/sys/doc/compiler.html</a>
-(see the table in section 2).
-
-<code>6</code> is the architecture letter for amd64 (or x86-64, if you prefer), while
-<code>g</code> stands for Go.
-</p>
-
 <h3 id="history">
 What is the history of the project?</h3>
 <p>