doc/go1.4.html: tweak http.Transport.DialTLS wording

It doesn't simplify, because it wasn't even possible before.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/164250043

doc/go1.4.html

@@ -678,8 +678,8 @@ Scheme.
 
 <li>The <a href="/pkg/net/http/"><code>net/http</code></a> package's
 <a href="/pkg/net/http/#Request"><code>Transport</code></a> type
-has a new <a href="/pkg/net/http/#Transport.DialTLS"><code>DialTLS</code></a> function
-that simplifies setting up TLS connections.
+has a new <a href="/pkg/net/http/#Transport.DialTLS"><code>DialTLS</code></a> hook
+that allows customizing the behavior of outbound TLS connections.
 </li>
 
 <li>