minor #14407 [Configuration] Update front_controllers_and_kernel.rst (lubo13)

This PR was merged into the 4.4 branch.

Discussion
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[Configuration] Update front_controllers_and_kernel.rst

I think this `appDevDebugProjectContainer.php`, `appDevUrlGenerator.php`, and `appDevUrlMatcher.php` are outdated, isn't it?

Commits
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1c99471 Update front_controllers_and_kernel.rst

Author: javiereguiluz

configuration/front_controllers_and_kernel.rst

@@ -244,15 +244,15 @@ the directory of the environment you're using (most commonly ``dev/`` while
 developing and debugging). While it can vary, the ``var/cache/dev/`` directory
 includes the following:
 
-``appDevDebugProjectContainer.php``
+``srcApp_KernelDevDebugContainer.php``
     The cached "service container" that represents the cached application
     configuration.
 
-``appDevUrlGenerator.php``
+``UrlGenerator.php``
     The PHP class generated from the routing configuration and used when
     generating URLs.
 
-``appDevUrlMatcher.php``
+``UrlMatcher.php``
     The PHP class used for route matching - look here to see the compiled regular
     expression logic used to match incoming URLs to different routes.