minor #17749 Add note about ResponseInterface::toStream() (henrikac)

This PR was submitted for the 6.2 branch but it was merged into the 5.4 branch instead.

Discussion
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Add note about `ResponseInterface::toStream()`

The docs for `HttpClient` mentions that [Symfony\Contracts\HttpClient\ResponseInterface](https://github.com/symfony/http-client-contracts/blob/main/ResponseInterface.php) provides a method `toStream` but looking at the source code one can see that this is not the case.

This PR removes the mention of `Symfony\Contracts\HttpClient\ResponseInterface::toStream` from the docs.

Commits
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e84e3e8 add note about ->toStream()

Author: OskarStark

http_client.rst

@@ -1013,6 +1013,10 @@ following methods::
     // returns detailed logs about the requests and responses of the HTTP transaction
     $httpLogs = $response->getInfo('debug');
 
+.. note::
+
+    ``$response->toStream()`` is part of :class:`Symfony\\Component\\HttpClient\\Response\\StreamableInterface`.
+
 .. note::
 
     ``$response->getInfo()`` is non-blocking: it returns *live* information