doc: add missing <code> to go1.1.html

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/8880043

doc/go1.1.html

@@ -938,7 +938,7 @@ matching the existing methods of <a href="/pkg/net/#TCPConn"><code>TCPConn</code
 The <a href="/pkg/net/http/"><code>net/http</code></a> package includes several new additions.
 <a href="/pkg/net/http/#ParseTime"><code>ParseTime</code></a> parses a time string, trying
 several common HTTP time formats.
-The <a href="/pkg/net/http/#Request.PostFormValue">PostFormValue</a> method of
+The <a href="/pkg/net/http/#Request.PostFormValue"><code>PostFormValue</code></a> method of
 <a href="/pkg/net/http/#Request"><code>Request</code></a> is like
 <a href="/pkg/net/http/#Request.FormValue"><code>FormValue</code></a> but ignores URL parameters.
 The <a href="/pkg/net/http/#CloseNotifier"><code>CloseNotifier</code></a> interface provides a mechanism