doc: fix installation $GOOS choices
The $GOOS choices text and combinations list should match.
R=adg
CC=golang-dev
https://golang.org/cl/3485046
diff --git a/doc/install.html b/doc/install.html
index 1c344e4..8df3d42 100644
--- a/doc/install.html
+++ b/doc/install.html
@@ -340,7 +340,8 @@
Choices for <code>$GOOS</code> are <code>linux</code>,
<code>freebsd</code>,
<code>darwin</code> (Mac OS X 10.5 or 10.6),
- and <code>nacl</code> (Native Client, an incomplete port).
+ <code>nacl</code> (Native Client, an incomplete port),
+ and <code>windows</code> (Windows, an incomplete port).
Choices for <code>$GOARCH</code> are <code>amd64</code> (64-bit x86, the most mature port),
<code>386</code> (32-bit x86), and
<code>arm</code> (32-bit ARM, an incomplete port).
