add example of props in ts

examples/snowpack/astro/components/Nav.hmx

@@ -1,3 +1,7 @@
+<script astro>
+  export let props: {version: string};
+</script>
+
 <nav class="snow-nav">
   <button id="toc-drawer-button" class="snow-nav-mobile-open" type="button" aria-expanded="false"
     aria-controls="nav-primary">

examples/snowpack/astro/components/Subnav.hmx

@@ -1,3 +1,11 @@
+<script astro>
+  export let props: { 
+    title: string, 
+    inputPath: string, 
+    headers: { text: string, slug: string }[] 
+  };
+</script>
+
 <script type="module" defer src="/js/index.js"></script>
 <aside class="snow-toc snow-toc__subnav snow-view-subnav">
   <h2 class="content-title">