Update readme.md

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

readme.md

@@ -662,7 +662,7 @@ Default `dns.lookup`
 
 Custom lookup function.
 
-The function signature is the same of `dns.lookup`, please refer to the Node.js documentation page for more information https://nodejs.org/api/dns.html#dns_dns_lookup_hostname_options_callback
+The function signature is the same as [`dns.lookup`](https://nodejs.org/api/dns.html#dns_dns_lookup_hostname_options_callback).
 
 ###### request