[minor] remove usage of Kernel::$rootDir from docs

jzawadzki · javiereguiluz · commit 9da96e1c8f59 · 2019-11-30T18:02:03.000+01:00
diff --git a/reference/configuration/kernel.rst b/reference/configuration/kernel.rst
@@ -105,7 +105,7 @@ method to return the right project directory::
 Cache Directory
 ~~~~~~~~~~~~~~~
 
-**type**: ``string`` **default**: ``$this->rootDir/cache/$this->environment``
+**type**: ``string`` **default**: ``$this->getProjectDir()/var/cache/$this->environment``
 
 This returns the absolute path of the cache directory of your Symfony project.
 It's calculated automatically based on the current
@@ -119,7 +119,7 @@ cache directory.
 Log Directory
 ~~~~~~~~~~~~~
 
-**type**: ``string`` **default**: ``$this->rootDir/log``
+**type**: ``string`` **default**: ``$this->getProjectDir()/var/log``
 
 .. deprecated:: 4.2
 
