Change duplicated redirect in examples (vercel#19479)

The code here should contain a regex path matching example, as stated in the comment; but it is the same as the wildcard path matching example above.

https://nextjs.org/docs/api-reference/next.config.js/redirects#regex-path-matching

examples/redirects/next.config.js

@@ -25,8 +25,8 @@ module.exports = {
       },
       // Regex Path Matching - The regex below will match `/post/123` but not `/post/abc`
       {
-        source: '/post/:slug*',
-        destination: '/news/:slug*',
+        source: '/post/:slug(\\d{1,})',
+        destination: '/news/:slug',
         permanent: false,
       },
     ]