Docs: Standardizing on "Android N" language in Preview docs.

Change-Id: I7398c137f5b0c04826cedb4c03c576322f0c941d
diff --git a/docs/html/preview/index.jd b/docs/html/preview/index.jd
index 778487d..337f6d7 100644
--- a/docs/html/preview/index.jd
+++ b/docs/html/preview/index.jd
@@ -37,7 +37,7 @@
         </a><!--<br>
         <a class="dac-hero-cta" href="{@docRoot}preview/support.html">
           <span class="dac-sprite dac-auto-chevron"></span>
-          Update to Developer Preview (final SDK)
+          Update to Android N (final SDK)
         </a><br>-->
       </div>
       <div class="col-9of16 col-pull-7of16 dac-hero-figure" style="margin-top:1.5em;padding-right:1.5em;">