Added an additional link about GPC

Author: pyllyukko

Diff for: README.md

@@ -274,7 +274,7 @@ Disable Firefox integrated metrics/reporting/experiments, disable potentially in
 * Disable querying Google Application Reputation database for downloaded binary files [ [1](https://www.mozilla.org/en-US/firefox/39.0/releasenotes/) [2](https://wiki.mozilla.org/Security/Application_Reputation) ]
 * Disable Pocket [ [1](https://support.mozilla.org/en-US/kb/save-web-pages-later-pocket-firefox) [2](https://github.com/pyllyukko/user.js/issues/143) ]
 * Disable "Recommended by Pocket" in Firefox Quantum
-* Enable Global Privacy Control (GPC) (Firefox >= 120) [ [1](https://support.mozilla.org/1/firefox/126.0/Linux/en-US/global-privacy-control) ]
+* Enable Global Privacy Control (GPC) (Firefox >= 120) [ [1](https://support.mozilla.org/1/firefox/126.0/Linux/en-US/global-privacy-control) [2](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Sec-GPC) ]
 
 ### Automatic connections
 

Diff for: user.js

@@ -640,6 +640,7 @@ user_pref("browser.newtabpage.activity-stream.feeds.section.topstories",	false);
 
 // PREF: Enable Global Privacy Control (GPC) (Firefox >= 120)
 // https://support.mozilla.org/1/firefox/126.0/Linux/en-US/global-privacy-control
+// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Sec-GPC
 user_pref("privacy.globalprivacycontrol.enabled",		true);
 
 /******************************************************************************