docs: fix overlapping sidebar bug,

but I think this re-introduces a bug in IE where the sidenav
position moves slightly left/right during scroll, but it's a
worthwhile compromise and will investigate a diff solution for that later.

Change-Id: Id1f2141b6638e199d1a4ad1d198a5a5aa45bf264

tools/droiddoc/templates-sdk/assets/css/fullscreen.css

@@ -179,7 +179,7 @@ body {
 
 #devdoc-nav.fixed,
 #devdoc-nav.fixed a.totop {
-  left:20px !important;
+  left:20px; /* !important ... for IE i think */
 }