minor symfony#16284 [Form] Additional hints when rendering the same form in different templates (kschrenk)

This PR was submitted for the 6.0 branch but it was squashed and merged into the 5.4 branch instead.

Discussion
----------

[Form] Additional hints when rendering the same form in different templates

There is the following tip mentioned in the documentation (see chapter [Processing forms)](https://symfony.com/doc/current/forms.html#processing-forms):

```
If you need to render and process the same form in different templates, use the render() function to embed the controller that processes the form:

{{ render(controller('App\\Controller\\TaskController::new')) }}
```

In my point of view this can lead to extra work especially when it comes to validation and rendering error messages.

So my proposal is to add a hint like
```
  But be careful because this might cause some extra work when it comes to submit and error handling.
  Symfony Validation will get more complex when you render the same form in different routes.
```

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Commits
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6092143 [Form] Additional hints when rendering the same form in different templates

Author: javiereguiluz

forms.rst

@@ -455,6 +455,9 @@ possible paths:
     .. code-block:: twig
 
         {{ render(controller('App\\Controller\\TaskController::new')) }}
+        
+    But be careful becaues this might cause some extra work when it comes to submit and error handling.
+    Symfony Validation will get more complex when you render the same form in different routes.
 
 .. _validating-forms: