Fix getStaticPaths example code (#10893)

* Fix getStaticPaths example code

* Update docs/basic-features/data-fetching.md
Co-authored-by: NTim Neutkens <tim@timneutkens.nl>

docs/basic-features/data-fetching.md

@@ -191,7 +191,9 @@ export async function getStaticPaths() {
   const posts = await res.json()
 
   // Get the paths we want to pre-render based on posts
-  const paths = posts.map(post => `/posts/${post.id}`)
+  const paths = posts.map(post => ({
+    params: {id: post.id}
+  }))
 
   // We'll pre-render only these paths at build time.
   // { fallback: false } means other routes should 404.