Fix broken link to sync and local storage properties.

BUG=

Review URL: https://codereview.chromium.org/947463002

Cr-Commit-Position: refs/heads/master@{#318261}

chrome/common/extensions/docs/templates/intros/storage.html

@@ -91,8 +91,7 @@ enormous amounts of material.
 of the storage API, and what happens
 when those limits are exceeded, please
 see the quota information for
-<a href="#sync-properties">sync</a> and
-<a href="#local-properties">local</a>.
+$(ref:sync) and $(ref:local).
 
 <h2 id="examples">Examples</h2>