doc: document r57.1

R=adg
CC=golang-dev
https://golang.org/cl/4471041

doc/devel/release.html

@@ -22,7 +22,7 @@ The r57 release corresponds to
 with additional bug fixes.
 This section highlights the most significant changes in this release.
 For a more detailed summary, see the
-The <a href="weekly.html#2011-04-27">weekly release notes</a>.
+<a href="weekly.html#2011-04-27">weekly release notes</a>.
 For complete information, see the
 <a href="http://code.google.com/p/go/source/list?r=release-branch.r57">Mercurial change list</a>.
 </p>
@@ -159,6 +159,10 @@ documentation.
 For other uses, see the <a href="/pkg/runtime/pprof/">runtime/pprof</a> documentation.
 </p>
 
+<h3 id="r57.minor">Minor revisions</h3>
+
+<p>r57.1 fixes a <a href="http://code.google.com/p/go/source/detail?r=ff2bc62726e7145eb2ecc1e0f076998e4a8f86f0">nil pointer dereference in http.FormFile</a>.</p>
+
 <h2 id="r56">r56 (released 2011/03/16)</h2>
 
 <p>