minor #19772 [Console] Update monolog_console.rst (suizumasahar01)

This PR was squashed before being merged into the 5.4 branch.

Discussion
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[Console] Update monolog_console.rst

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Regarding https://symfony.com/doc/5.x/logging/monolog_console.html, current sample doesn't work properly.
Added "parent::__construct();" to sample code.

Commits
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82723f1 [Console] Update monolog_console.rst

logging/monolog_console.rst

@@ -46,6 +46,7 @@ The example above could then be rewritten as::
 
         public function __construct(LoggerInterface $logger)
         {
+            parent::__construct();
             $this->logger = $logger;
         }