Update snippets/vercel-json-generator.mdx (#2377)

Co-authored-by: mintlify[bot] <109931778+mintlify[bot]@users.noreply.github.com>

Author: mintlify[bot]

snippets/vercel-json-generator.mdx

@@ -32,6 +32,10 @@ export const VercelJsonGenerator = () => {
         source: `/${subpath}/robots.txt`,
         destination: `https://${subdomain}.mintlify.app/robots.txt`
       },
+      {
+        source: `/${subpath}/mcp`,
+        destination: `https://${subdomain}.mintlify.app/mcp`
+      },
       {
         source: `/${subpath}/:path*`,
         destination: `https://${subdomain}.mintlify.app/${subpath}/:path*`