docs: modify css to support sidenav headings with span, instead of h2
because I suspect the h2 is sending mixed signals to search engines for result snippets

Change-Id: I80f13774f25439efebcade1b9db41c005018d2aa
diff --git a/tools/droiddoc/templates-sdk/assets/android-developer-docs.css b/tools/droiddoc/templates-sdk/assets/android-developer-docs.css
index 8e9e5bb..b470ba0 100644
--- a/tools/droiddoc/templates-sdk/assets/android-developer-docs.css
+++ b/tools/droiddoc/templates-sdk/assets/android-developer-docs.css
@@ -72,7 +72,8 @@
   zoom:1;
 }
 
-#side-nav li h2 {
+#side-nav li span.heading {
+  display:block;
   font-size:12px;
   font-weight: bold;
   margin:.5em 0 0 0;