minor symfony#10225 [HttpFoundation] Broken nginx XSendfile link (NicolasDievart)

This PR was merged into the 2.8 branch.

Discussion
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[HttpFoundation] Broken nginx XSendfile link

The link that goes to the Nginx website to the XSendfile documentation is broken and is redirected to the homepage of the nginx website.

I changed it to the example doc which explain the XSendfile and the associted standard X-Accel

Commits
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c824a61 Broken nginx XSendfile link

Author: javiereguiluz

components/http_foundation.rst

@@ -616,7 +616,7 @@ Learn More
     /http_cache/*
 
 .. _Packagist: https://packagist.org/packages/symfony/http-foundation
-.. _Nginx: http://wiki.nginx.org/XSendfile
+.. _Nginx: https://www.nginx.com/resources/wiki/start/topics/examples/xsendfile/
 .. _Apache: https://tn123.org/mod_xsendfile/
 .. _`JSON Hijacking`: http://haacked.com/archive/2009/06/25/json-hijacking.aspx
 .. _OWASP guidelines: https://www.owasp.org/index.php/OWASP_AJAX_Security_Guidelines#Always_return_JSON_with_an_Object_on_the_outside