[DotEnv] Fix incorrect way to modify .env path

Author: alexandre-daubois

configuration.rst

@@ -936,22 +936,47 @@ Storing Environment Variables In Other Files
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 By default, the environment variables are stored in the ``.env`` file located
-at the root of your project. However, you can store them in other file by
-setting the ``SYMFONY_DOTENV_PATH`` environment variable to the absolute path of
-that custom file.
+at the root of your project. However, you can store them in other files in
+multiple ways:
+
+* By calling the :method:`Symfony\\Component\\Dotenv\\Dotenv::bootEnv`
+  method with the path to the file as the first argument::
+
+    use Symfony\Component\Dotenv\Dotenv;
+
+    (new Dotenv())->bootEnv(dirname(__DIR__).'my/custom/path/to/.env');
+
+* By adding the following directives to your ``composer.json`` file:
+
+  .. code-block:: json
+
+      {
+          // ...
+          "extra": {
+              // ...
+              "runtime": {
+                  "dotenv_path": "my/custom/path/to/.env"
+              }
+          }
+      }
+
+* By setting the ``APP_RUNTIME_OPTIONS`` environment variable like this
+  in your PHP code::
+
+    $_SERVER['APP_RUNTIME_OPTIONS'] = ['dotenv_path' => 'my/custom/path/to/.env'];
+
+.. note::
+
+    The first option is only possible when using the Dotenv component as standalone
+    or when the Runtime component is not used. The second and third options are
+    automatically enabled when using the Runtime component.
 
 Symfony will then look for the environment variables in that file, but also in
 the local and environment-specific files (e.g. ``.*.local`` and
 ``.*.<environment>.local``). Read
 :ref:`how to override environment variables <configuration-multiple-env-files>`
 to learn more about this.
 
-.. caution::
-
-    The ``SYMFONY_DOTENV_PATH`` environment variable must be defined at the
-    system level (e.g. in your web server configuration) and not in any default
-    or custom ``.env`` file.
-
 .. versionadded:: 7.1
 
     The ``SYMFONY_DOTENV_PATH`` environment variable was introduced in Symfony 7.1.