doc: add Array type in http request headers

The http.request allows sending headers as an array of strings.

Fixes: #57986

Author: mikaws

doc/api/http.md

@@ -3818,7 +3818,7 @@ changes:
   * `family` {number} IP address family to use when resolving `host` or
     `hostname`. Valid values are `4` or `6`. When unspecified, both IP v4 and
     v6 will be used.
-  * `headers` {Object} An object containing request headers.
+  * `headers` {Object|Array} An object or an array of strings containing request headers. The array is in the same format as request.rawHeaders.
   * `hints` {number} Optional [`dns.lookup()` hints][].
   * `host` {string} A domain name or IP address of the server to issue the
     request to. **Default:** `'localhost'`.