Add fill_extra_context option to the symfony documentation (#9824)

* Add fill_extra_context option to the symfony documentation

* Add also the context data to test example

* Update docs/platforms/php/guides/symfony/index.mdx

Co-authored-by: vivianyentran <20403606+vivianyentran@users.noreply.github.com>

---------

Co-authored-by: vivianyentran <20403606+vivianyentran@users.noreply.github.com>

docs/platforms/php/guides/symfony/index.mdx

@@ -42,6 +42,7 @@ monolog:
             type: sentry
             level: !php/const Monolog\Logger::ERROR
             hub_id: Sentry\State\HubInterface
+            fill_extra_context: true # Enables sending monolog context to Sentry
 ```
 
 Additionally, you can register the `PsrLogMessageProcessor` to resolve PSR-3 placeholders in reported messages:
@@ -84,7 +85,7 @@ class SentryTestController extends AbstractController
     public function testLog()
     {
         // the following code will test if monolog integration logs to sentry
-        $this->logger->error('My custom logged error.');
+        $this->logger->error('My custom logged error.', ['some' => 'Context Data']);
 
         // the following code will test if an uncaught exception logs to sentry
         throw new \RuntimeException('Example exception.');