fix modulepreload typo

Author: e111077

Diff for: packages/lit-dev-content/site/_includes/default.html

@@ -8,7 +8,7 @@
     <meta name="description" content="Simple. Fast. Web Components.">
     <link rel="icon" href="{{ site.baseurl }}/images/flame-favicon.svg">
     <link rel="mask-icon" href="{{ site.baseurl }}/images/flame-favicon.svg" color="#324fff">
-    <script type="modulepreload" src="{{ site.baseurl }}/js/tslib.js"></script>
+    <link rel="modulepreload" href="{{ site.baseurl }}/js/tslib.js">
     {% if not env.DEV %}
     <link rel="modulepreload" href="{{ site.baseurl }}/js/lit.js">
     {% endif %}