minor #10195 Updated link to Event Listeners page (ThomasLandauer, xabbuh)

This PR was merged into the 2.8 branch.

Discussion
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Updated link to Event Listeners page

Not sure if I got it right (preview isn't showing it) - the page I wanted to link to is https://symfony.com/doc/current/bundles/DoctrineBundle/entity-listeners.html

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Commits
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58647a0 fix the markup
567616f Changing to absolute url, as requested
f521534 Updated link to Event Listeners page

Author: xabbuh

doctrine/event_listeners_subscribers.rst

@@ -269,4 +269,4 @@ to the tag like so:
     definitions which are described :doc:`in their own article </service_container/lazy_services>`
 
 .. _`The Event System`: http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/events.html
-.. _`the Doctrine Documentation`: http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/events.html#entity-listeners
+.. _`the Doctrine Documentation`: https://symfony.com/doc/current/bundles/DoctrineBundle/entity-listeners.html