minor #15011 remove unsupported trusted header config values (xabbuh)

This PR was merged into the 5.2 branch.

Discussion
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remove unsupported trusted header config values

fixes symfony/symfony#40247

Commits
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fd02abe remove unsupported trusted header config values

Author: javiereguiluz

deployment/proxies.rst

@@ -37,9 +37,6 @@ and what headers your reverse proxy uses to send information:
             trusted_headers: ['x-forwarded-for', 'x-forwarded-host', 'x-forwarded-proto', 'x-forwarded-port']
             // or, if your proxy instead uses the "Forwarded" header
             trusted_headers: ['forwarded']
-            // or, if you're using a wellknown proxy
-            trusted_headers: [!php/const Symfony\\Component\\HttpFoundation\\Request::HEADER_X_FORWARDED_AWS_ELB]
-            trusted_headers: [!php/const Symfony\\Component\\HttpFoundation\\Request::HEADER_X_FORWARDED_TRAEFIK]
 
     .. code-block:: xml
 
@@ -80,9 +77,6 @@ and what headers your reverse proxy uses to send information:
             'trusted_headers' => ['x-forwarded-for', 'x-forwarded-host', 'x-forwarded-proto', 'x-forwarded-port'],
             // or, if your proxy instead uses the "Forwarded" header
             'trusted_headers' => ['forwarded'],
-            // or, if you're using a wellknown proxy
-            'trusted_headers' => [Request::HEADER_X_FORWARDED_AWS_ELB],
-            'trusted_headers' => [Request::HEADER_X_FORWARDED_TRAEFIK],
         ]);
 
 .. deprecated:: 5.2
@@ -135,9 +129,6 @@ In this case, you'll need to - *very carefully* - trust *all* proxies.
             // run time by $_SERVER['REMOTE_ADDR'])
             trusted_proxies: '127.0.0.1,REMOTE_ADDR'
 
-            // if you're using ELB, otherwise use another Request::HEADER-* constant
-            trusted_headers: [!php/const Symfony\\Component\\HttpFoundation\\Request::HEADER_X_FORWARDED_AWS_ELB, '!x-forwarded-host', '!x-forwarded-prefix']
-
 That's it! It's critical that you prevent traffic from all non-trusted sources.
 If you allow outside traffic, they could "spoof" their true IP address and
 other information.