docs: added notes libcurl

Author: ddevsr

tests/system/HTTP/CURLRequestTest.php

@@ -1216,7 +1216,7 @@ public function testForceResolveIPUnknown(): void
     /**
      * @return array<string, array<string, bool|int|string>>
      *
-     * @see https://linux.die.net/man/3/curl_easy_setopt
+     * @see https://curl.se/libcurl/c/CURLOPT_DNS_CACHE_TIMEOUT.html
      */
     public static function provideDNSCacheTimeout(): iterable
     {

user_guide_src/source/libraries/curlrequest.rst

@@ -256,11 +256,13 @@ dns_cache_timeout
 
 .. versionadded:: 4.7.0
 
-By default, CodeIgniter does not change the DNS Cache Timeout value (``120`` seconds). If you need to
+By default PHP, CodeIgniter does not change the DNS Cache Timeout value (``120`` seconds). If you need to
 modify this value, you can do so by passing an amount of time in seconds with the ``dns_cache_timeout`` option.
 
 .. literalinclude:: curlrequest/037.php
 
+.. note:: Based on documentation `libcurl <https://curl.se/libcurl/c/CURLOPT_DNS_CACHE_TIMEOUT.html>`__, you can set to zero to completely disable caching, or set to -1 to make the cached entries remain forever.
+
 form_params
 ===========