Reflect renaming from private to hidden

As applied in the code repository by symfony/symfony#20266

Author: wouterj

console/private_commands.rst

@@ -1,16 +1,15 @@
-Creating Private Console Commands
-=================================
+How to Hide Console Commands
+============================
 
-Console commands are public by default, meaning that they are listed alongside
-other commands when executing the console application script without arguments
-or when using the ``list`` command.
+By default, all console commands are listed when executing the console application
+script without arguments or when using the ``list`` command.
 
 However, sometimes commands are not intended to be executed by end-users; for
 example, commands for the legacy parts of the application, commands exclusively
 executed through scheduled tasks, etc.
 
-In those cases, you can define the command as **private** setting the
-``setPublic()`` method to ``false`` in the command configuration::
+In those cases, you can define the command as **hidden** by setting the
+``setHidden()`` method to ``true`` in the command configuration::
 
     // src/AppBundle/Command/FooCommand.php
     namespace AppBundle\Command;
@@ -23,12 +22,11 @@ In those cases, you can define the command as **private** setting the
         {
             $this
                 ->setName('app:foo')
+                ->setHidden(true)
                 // ...
-                ->setPublic(false)
             ;
         }
     }
 
-Private commands behave the same as public commands and they can be executed as
-before, but they are no longer displayed in command listings, so end-users are
-not aware of their existence.
+Hidden commands behave the same as normal commands but they are no longer displayed
+in command listings, so end-users are not aware of their existence.