feature #12526 Documented $response->getInfo('canceled') (Toflar)

This PR was squashed before being merged into the 4.4 branch (closes #12526).

Discussion
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Documented $response->getInfo('canceled')

Documented the new `canceled` information introduced in symfony/symfony#34044.

Reading the docs, I wonder if we need to catch any `Throwable` and also set `canceled` to `true` @nicolas-grekas?

Commits
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71cff04 Documented $response->getInfo('canceled')

Author: OskarStark

components/http_client.rst

@@ -417,6 +417,9 @@ Or throw an exception from a progress callback::
 The exception will be wrapped in an instance of ``TransportExceptionInterface``
 and will abort the request.
 
+In case the response was canceled using ``$response->cancel()``,
+``$response->getInfo('canceled')`` will return ``true``.
+
 Handling Exceptions
 ~~~~~~~~~~~~~~~~~~~