feat: corrects md to use a manual slug

www/src/pages/md/[slug].astro

@@ -5,7 +5,7 @@ import Layout from '../../layouts/Layout.astro';
 export async function getStaticPaths() {
   const posts = await getCollection('posts', ({ data }) => data.draft !== true);
   return posts.map(post => ({
-    params: { slug: post.id },
+    params: { slug: post.data.slug },
     props: { post }
   }));
 }