minor #20141 [Config] Match Yaml configuration and Tree (devojifr)

This PR was merged into the 5.4 branch.

Discussion
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[Config] Match Yaml configuration and Tree

The documentation shows Yaml configuration using a mysql string as a default value for default_connection configuration.
It may be reflected into the Tree.
Even if this is not an error, it may help to remain consistent.

Commits
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309141a [Config] Match Yaml configuration and Tree

Author: javiereguiluz

components/config/definition.rst

@@ -81,7 +81,7 @@ reflect the real structure of the configuration values::
                 ->defaultTrue()
             ->end()
             ->scalarNode('default_connection')
-                ->defaultValue('default')
+                ->defaultValue('mysql')
             ->end()
         ->end()
     ;