minor #9123 add an alias for the profiler service (xabbuh)

This PR was merged into the 4.0 branch.

Discussion
----------

add an alias for the profiler service

fixes #9122

Commits
-------

a423d8c add an alias for the profiler service

Author: javiereguiluz

profiler/matchers.rst

@@ -29,3 +29,35 @@ class in your controllers to manage the profiler programmatically::
             // ...
         }
     }
+
+In order for the profiler to be injected into your controller you need to
+create an alias pointing to the existing ``profiler`` service:
+
+.. configuration-block::
+
+    .. code-block:: yaml
+
+        # config/services.yaml
+        services:
+            Symfony\Component\HttpKernel\Profiler\Profiler: '@profiler'
+
+    .. code-block:: xml
+
+        <!-- config/services.xml -->
+        <?xml version="1.0" encoding="UTF-8" ?>
+        <container xmlns="http://symfony.com/schema/dic/services"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xsi:schemaLocation="http://symfony.com/schema/dic/services
+                http://symfony.com/schema/dic/services/services-1.0.xsd">
+
+            <services>
+                <service id="Symfony\Component\HttpKernel\Profiler\Profiler" alias="profiler" />
+            </services>
+        </container>
+
+    .. code-block:: php
+
+        // config/services.php
+        use Symfony\Component\HttpKernel\Profiler\Profiler;
+
+        $container->setAlias(Profiler::class, 'profiler');