minor #19308 [Logger] Switching to more modern config format (ThomasLandauer)

This PR was squashed before being merged into the 5.4 branch.

Discussion
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[Logger] Switching to more modern config format

Page: https://symfony.com/doc/5.4/logging/channels_handlers.html#switching-a-channel-to-a-different-handler

Removing all occurrences of config file location `/prod/` in favor of an in-file switch (e.g. `when@prod`).

Syntax is taken from https://symfony.com/doc/current/configuration.html#configuration-environments

Commits
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b3ca593 [Logger] Switching to more modern config format

Author: javiereguiluz

logging/channels_handlers.rst

@@ -23,27 +23,27 @@ Switching a Channel to a different Handler
 Now, suppose you want to log the ``security`` channel to a different file.
 To do this, create a new handler and configure it to log only messages
 from the ``security`` channel. The following example does that only in the
-``prod`` :ref:`configuration environment <configuration-environments>` but you
-can do it in any (or all) environments:
+``prod`` :ref:`configuration environment <configuration-environments>`:
 
 .. configuration-block::
 
     .. code-block:: yaml
 
-        # config/packages/prod/monolog.yaml
-        monolog:
-            handlers:
-                security:
-                    # log all messages (since debug is the lowest level)
-                    level:    debug
-                    type:     stream
-                    path:     '%kernel.logs_dir%/security.log'
-                    channels: [security]
-
-                # an example of *not* logging security channel messages for this handler
-                main:
-                    # ...
-                    # channels: ['!security']
+        # config/packages/monolog.yaml
+        when@prod:
+            monolog:
+                handlers:
+                    security:
+                        # log all messages (since debug is the lowest level)
+                        level:    debug
+                        type:     stream
+                        path:     '%kernel.logs_dir%/security.log'
+                        channels: [security]
+
+                    # an example of *not* logging security channel messages for this handler
+                    main:
+                        # ...
+                        # channels: ['!security']
 
     .. code-block:: xml
 
@@ -56,12 +56,14 @@ can do it in any (or all) environments:
                 http://symfony.com/schema/dic/monolog
                 https://symfony.com/schema/dic/monolog/monolog-1.0.xsd">
 
-            <monolog:config>
-                <monolog:handler name="security" type="stream" path="%kernel.logs_dir%/security.log">
-                    <monolog:channels>
-                        <monolog:channel>security</monolog:channel>
-                    </monolog:channels>
-                </monolog:handler>
+            <when env="prod">
+                <monolog:config>
+                    <monolog:handler name="security" type="stream" path="%kernel.logs_dir%/security.log">
+                        <monolog:channels>
+                            <monolog:channel>security</monolog:channel>
+                        </monolog:channels>
+                    </monolog:handler>
+            </when>
 
                 <monolog:handler name="main" type="stream" path="%kernel.logs_dir%/main.log">
                     <!-- ... -->
@@ -75,18 +77,21 @@ can do it in any (or all) environments:
     .. code-block:: php
 
         // config/packages/prod/monolog.php
+        use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
         use Symfony\Config\MonologConfig;
 
-        return static function (MonologConfig $monolog) {
-            $monolog->handler('security')
-                ->type('stream')
-                ->path('%kernel.logs_dir%/security.log')
-                ->channels()->elements(['security']);
+        return static function (MonologConfig $monolog, ContainerConfigurator $container) {
+            if ('prod' === $container->env()) {
+                $monolog->handler('security')
+                    ->type('stream')
+                    ->path(param('kernel.logs_dir') . \DIRECTORY_SEPARATOR . 'security.log')
+                    ->channels()->elements(['security']);
 
-            $monolog->handler('main')
-                 // ...
+                $monolog->handler('main')
+                     // ...
 
-                ->channels()->elements(['!security']);
+                    ->channels()->elements(['!security']);
+            }
         };
 
 .. caution::
@@ -131,13 +136,13 @@ You can also configure additional channels without the need to tag your services
 
     .. code-block:: yaml
 
-        # config/packages/prod/monolog.yaml
+        # config/packages/monolog.yaml
         monolog:
             channels: ['foo', 'bar', 'foo_bar']
 
     .. code-block:: xml
 
-        <!-- config/packages/prod/monolog.xml -->
+        <!-- config/packages/monolog.xml -->
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xmlns:monolog="http://symfony.com/schema/dic/monolog"
@@ -155,7 +160,7 @@ You can also configure additional channels without the need to tag your services
 
     .. code-block:: php
 
-        // config/packages/prod/monolog.php
+        // config/packages/monolog.php
         use Symfony\Config\MonologConfig;
 
         return static function (MonologConfig $monolog) {