Apply suggestion - add namespace

Co-authored-by: Oskar Stark <oskarstark@googlemail.com>

Author: ybenhssaien

console.rst

@@ -389,13 +389,13 @@ console::
 
 .. caution::
 
-    When testing commands using the ``ApplicationTester`` class, don't forget to disable the auto exist flag :
+    When testing commands using the :class:`Symfony\\Component\\Console\\Tester\\ApplicationTester`
+    class, don't forget to disable the auto exit flag::
 
         $application = new Application();
-        
         $application->setAutoExit(false);
         
-        $applicationTester = new ApplicationTester($application);
+        $tester = new ApplicationTester($application);
 
 .. note::