fix(mdb): fix 404 (#5029)

Author: ldecarvalho-doc

pages/managed-mongodb-databases/index.mdx

@@ -63,7 +63,7 @@ content:
     productLogo="cli"
     title="Managed MongoDB® API"
     description="Manage your document Database Instances using the Scaleway API."
-    url="https://www.scaleway.com/en/developers/api/document_db/"
+    url="https://www.scaleway.com/en/developers/api/managed-database-mongodb/"
     label="Go to Managed MongoDB® API"
 />