doc/1.9: fix stray html in CL 53030

Change-Id: Ib4102b1e2a8863712f725c4d1e37fdbe3dfe3c07
Reviewed-on: https://go-review.googlesource.com/53210
Reviewed-by: Brad Fitzpatrick <[email protected]>

Author: dmitris

doc/go1.9.html

@@ -477,7 +477,7 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
 
     If any SAN extension, including with no DSN names, is present
     in the certificate, then the Common Name from
-    <a href="#pkg/crypto/x509/#Certificate.Subject"><code>Subject</code>code></a> is ignored.
+    <a href="#pkg/crypto/x509/#Certificate.Subject"><code>Subject</code></a> is ignored.
     In previous releases, the code tested only whether DNS-name SANs were
     present in a certificate.
     </p>