minor #8814 remove CompilerPassInterface from kernel (andrewtch)

This PR was merged into the 4.0 branch.

Discussion
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remove CompilerPassInterface from kernel

It is not needed here - `build` methods is a part of `Kernel`, but `CompilerPassInterface` defines `process`.

Commits
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9b27700 remove CompilerPassInterface from kernel

Author: xabbuh

service_container/compiler_passes.rst

@@ -17,11 +17,10 @@ Compiler passes are registered in the ``build()`` method of the application kern
 
     use App\DependencyInjection\Compiler\CustomPass;
     use Symfony\Bundle\FrameworkBundle\Kernel\MicroKernelTrait;
-    use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
     use Symfony\Component\DependencyInjection\ContainerBuilder;
     use Symfony\Component\HttpKernel\Kernel as BaseKernel;
 
-    class Kernel extends BaseKernel implements CompilerPassInterface
+    class Kernel extends BaseKernel
     {
         use MicroKernelTrait;