doc: add hints to http.request() options

Author: lpinca

doc/api/http.md

@@ -2810,6 +2810,7 @@ changes:
     `hostname`. Valid values are `4` or `6`. When unspecified, both IP v4 and
     v6 will be used.
   * `headers` {Object} An object containing request headers.
+  * `hints` {number} Optional [`dns.lookup()` hints][].
   * `host` {string} A domain name or IP address of the server to issue the
     request to. **Default:** `'localhost'`.
   * `hostname` {string} Alias for `host`. To support [`url.parse()`][],