minor #18167 Update the example provided in the documentation for Development Versus Production: Environments (Ionut Enache)

This PR was merged into the 5.4 branch.

Discussion
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Update the example provided in the documentation for Development Versus Production: Environments

The example provided in the [Development Versus Production: Environments](https://symfony.com/doc/current/quick_tour/the_architecture.html#development-versus-production-environments) section of the [The Architecture](https://symfony.com/doc/current/quick_tour/the_architecture.html) documentation page is outdated since it is using the old way of splitting the configuration per environment.

The default Symfony project created via the binary (or alternatives) is using the new single-file approach with `when@<environment>`.

This PR changes the example provided with a new one that is describing the single-file approach.

Linked issue: #18165

Commits
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e954966 Update the example provided in the Development Versus Production: Environments section

Author: javiereguiluz

quick_tour/the_architecture.rst

@@ -237,31 +237,66 @@ whenever needed.
 But what about when you deploy to production? We will need to hide those tools and
 optimize for speed!
 
-This is solved by Symfony's *environment* system and there are three: ``dev``, ``prod``
-and ``test``. Based on the environment, Symfony loads different files in the ``config/``
-directory:
-
-.. code-block:: text
-
-    config/
-    ├─ services.yaml
-    ├─ ...
-    └─ packages/
-        ├─ framework.yaml
-        ├─ ...
-        ├─ **dev/**
-            ├─ monolog.yaml
-            └─ ...
-        ├─ **prod/**
-            └─ monolog.yaml
-        └─ **test/**
-            ├─ framework.yaml
-            └─ ...
-    └─ routes/
-        ├─ annotations.yaml
-        └─ **dev/**
-            ├─ twig.yaml
-            └─ web_profiler.yaml
+This is solved by Symfony's *environment* system and there are three environments a
+typical Symfony application begins with: ``dev``, ``prod``, and ``test``. You can define
+options for specific environments in the configuration files from the ``config/``
+directory using the special ``when`` keyword:
+
+.. configuration-block::
+
+        .. code-block:: yaml
+
+            # config/packages/routing.yaml
+            framework:
+                router:
+                    utf8: true
+
+            when@prod:
+                framework:
+                    router:
+                        strict_requirements: null
+
+        .. code-block:: xml
+
+            <!-- config/packages/framework.xml -->
+            <?xml version="1.0" encoding="UTF-8" ?>
+            <container xmlns="http://symfony.com/schema/dic/services"
+                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+                xmlns:framework="http://symfony.com/schema/dic/symfony"
+                xsi:schemaLocation="http://symfony.com/schema/dic/services
+                    https://symfony.com/schema/dic/services/services-1.0.xsd
+                    http://symfony.com/schema/dic/symfony
+                    https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
+
+                <framework:config>
+                    <framework:router utf8="true"/>
+                </framework:config>
+
+                <when env="prod">
+                    <framework:config>
+                        <framework:router strict-requirements="null"/>
+                    </framework:config>
+                </when>
+            </container>
+
+        .. code-block:: php
+
+            // config/packages/framework.php
+            namespace Symfony\Component\DependencyInjection\Loader\Configurator;
+
+            use Symfony\Config\FrameworkConfig;
+
+            return static function (FrameworkConfig $framework, ContainerConfigurator $containerConfigurator) {
+                $framework->router()
+                    ->utf8(true)
+                ;
+
+                if ('prod' === $containerConfigurator->env()) {
+                    $framework->router()
+                        ->strictRequirements(null)
+                    ;
+                }
+            };
 
 This is a *powerful* idea: by changing one piece of configuration (the environment),
 your app is transformed from a debugging-friendly experience to one that's optimized