[release-branch.go1.11] doc: document Go 1.11.1

Updates #27953

Change-Id: I2f1a55e15dc5737a5a06bd894c46b2c4705f338c
Reviewed-on: https://go-review.googlesource.com/138858
Reviewed-by: Filippo Valsorda <filippo@golang.org>
(cherry picked from commit f99fc3a)
Reviewed-on: https://go-review.googlesource.com/138859
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

Author: katiehockman

doc/devel/release.html

@@ -30,6 +30,17 @@ <h2 id="go1.11">go1.11 (released 2018/08/24)</h2>
 Read the <a href="/doc/go1.11">Go 1.11 Release Notes</a> for more information.
 </p>
 
+<h3 id="go1.11.minor">Minor revisions</h3>
+
+<p>
+go1.11.1 (released 2018/10/01) includes fixes to the compiler, documentation, go
+command, runtime, and the <code>crypto/x509</code>, <code>encoding/json</code>,
+<code>go/types</code>, <code>net</code>, <code>net/http</code>, and
+<code>reflect</code> packages.
+See the <a href="https://github.com/golang/go/issues?q=milestone%3AGo1.11.1">Go
+1.11.1 milestone</a> on our issue tracker for details.
+</p>
+
 <h2 id="go1.10">go1.10 (released 2018/02/16)</h2>
 
 <p>