minor #11232 Fix the example about overriding the getProjectDir method (stof)

This PR was merged into the 3.4 branch.

Discussion
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Fix the example about overriding the getProjectDir method

This method must return the canonical path for things to work fine everywhere.

Commits
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d2e3e6b Fix the example about overriding the getProjectDir method

Author: javiereguiluz

deployment.rst

@@ -231,7 +231,7 @@ kernel and return your project's root directory::
 
         public function getProjectDir()
         {
-            return __DIR__.'/..';
+            return dirname(__DIR__);
         }
     }