Update docs "Troubleshooting -> HTTPs and Redirects" section

Author: c1tru55

docs/troubleshooting.md

@@ -6,7 +6,13 @@ If you work on linux and cannot edit some of the project files right after the f
 
 ## HTTPs and Redirects
 
-If Symfony is generating an internal redirect for an `https://` url, but the resulting url is `http://`, you have to uncomment the `TRUSTED_PROXIES` setting in your `.env` file.
+If Symfony is generating an internal redirect for an `https://` url, but the resulting url is `http://`, you have to uncomment the `TRUSTED_PROXIES` setting in your `.env` file and add this line in `config/packages/framework.yaml`:
+```
+# config/packages/framework.yaml
+framework:
+    trusted_proxies: '%env(TRUSTED_PROXIES)%'
+```
+
 For more details see the [Symfony internal redirect documentation](https://symfony.com/doc/current/routing.html#redirecting-to-urls-and-routes-directly-from-a-route).
 
 ## TLS/HTTPS Issues