minor #15306 [FrameworkBundle] Document env vars in framework.ide (javiereguiluz)

This PR was squashed before being merged into the 5.3-dev branch.

Discussion
----------

[FrameworkBundle] Document env vars in framework.ide

This fixes #15303.

`@MatTheCat`, please review this. Thank you!

Commits
-------

7f580b7 [FrameworkBundle] Document env vars in framework.ide

Author: javiereguiluz

reference/configuration/framework.rst

@@ -461,10 +461,52 @@ doubling them to prevent Symfony from interpreting them as container parameters)
         };
 
 Since every developer uses a different IDE, the recommended way to enable this
-feature is to configure it on a system level. This can be done by setting the
-``xdebug.file_link_format`` option in your ``php.ini`` configuration file. The
-format to use is the same as for the ``framework.ide`` option, but without the
-need to escape the percent signs (``%``) by doubling them:
+feature is to configure it on a system level. First, you can set its value to
+some environment variable that stores the name of the IDE/editor:
+
+.. configuration-block::
+
+    .. code-block:: yaml
+
+        # config/packages/framework.yaml
+        framework:
+            # the env var stores the IDE/editor name (e.g. 'phpstorm', 'vscode', etc.)
+            ide: '%env(resolve:CODE_EDITOR)%'
+
+    .. 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">
+
+            <!-- the env var stores the IDE/editor name (e.g. 'phpstorm', 'vscode', etc.) -->
+            <framework:config ide="%env(resolve:CODE_EDITOR)%"/>
+        </container>
+
+    .. code-block:: php
+
+        // config/packages/framework.php
+        use Symfony\Config\FrameworkConfig;
+
+        return static function (FrameworkConfig $framework) {
+            // the env var stores the IDE/editor name (e.g. 'phpstorm', 'vscode', etc.)
+            $framework->ide('%env(resolve:CODE_EDITOR)%');
+        };
+
+.. versionadded:: 5.3
+
+    The option to use env vars in the ``framework.ide`` option was introduced
+    in Symfony 5.3.
+
+Another alternative is to set the ``xdebug.file_link_format`` option in your
+``php.ini`` configuration file. The format to use is the same as for the
+``framework.ide`` option, but without the need to escape the percent signs
+(``%``) by doubling them:
 
 .. code-block:: ini