Add data-sync-storage-key to tabs script (#115)

Author: colegoldsmith

src/partials/body-end-scripts.hbs

@@ -1,5 +1,5 @@
 <script id="site-script" src="{{{uiRootPath}}}/js/site.js" data-ui-root-path="{{{uiRootPath}}}"></script>
-<script async src="{{{uiRootPath}}}/js/vendor/tabs.js"></script>
+<script data-sync-storage-key="preferred-tab" async src="{{{uiRootPath}}}/js/vendor/tabs.js"></script>
 <script async src="{{{uiRootPath}}}/js/vendor/highlight.js"></script>
 <script async src="{{{uiRootPath}}}/js/vendor/zooming.js"></script>