Fix snowpack test (#21)

Using the new `---` syntax, it must be at the top of the file. If it's not it will loop indefinitely.

examples/snowpack/astro/pages/plugins.hmx

@@ -1,3 +1,21 @@
+---
+  import news from '../data/news.json';
+  import users from '../data/users.json';
+  import PluginSearchPage from '../components/PluginSearchPage.jsx';
+
+  export const layout = 'layouts/main.hmx';
+
+  export function setup({ context }) {
+    return {
+      context: {
+        title: 'The Snowpack Plugin Catalog',
+        description:
+          'Snowpack plugins allow for configuration-minimal tooling integration.',
+      },
+    };
+  }
+---
+
 <style lang="scss">
   .intro {
     margin-top: 1rem;
@@ -38,24 +56,6 @@
   }
 </style>
 
----
-  import news from '../data/news.json';
-  import users from '../data/users.json';
-  import PluginSearchPage from '../components/PluginSearchPage.jsx';
-
-  export const layout = 'layouts/main.hmx';
-
-  export function setup({ context }) {
-    return {
-      context: {
-        title: 'The Snowpack Plugin Catalog',
-        description:
-          'Snowpack plugins allow for configuration-minimal tooling integration.',
-      },
-    };
-  }
----
-
 <h2 class="content-title">{ context.title }</h2>
 
 <h3 class="pluginPage-subheading">