minor #13574 fix link to DBAL Connection class (xabbuh)

This PR was merged into the 3.4 branch.

Discussion
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fix link to DBAL Connection class

Thanks to @abelardolg for reporting this on Slack.

Commits
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603b6b3 fix link to DBAL Connection class

Author: javiereguiluz

components/cache/adapters/pdo_doctrine_dbal_adapter.rst

@@ -47,5 +47,5 @@ third, and forth parameters::
     calling its ``prune()`` method.
 
 .. _`PDO`: http://php.net/manual/en/class.pdo.php
-.. _`Doctrine DBAL Connection`: https://github.com/doctrine/dbal/blob/master/lib/Doctrine/DBAL/Connection.php
+.. _`Doctrine DBAL Connection`: https://github.com/doctrine/dbal/blob/master/src/Connection.php
 .. _`Data Source Name (DSN)`: https://en.wikipedia.org/wiki/Data_source_name