minor #21382 [DependencyInjection] Remove an unused docblock (dunglas)

This PR was merged into the 3.3-dev branch.

Discussion
----------

[DependencyInjection] Remove an unused docblock

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

The removal of this doc block was forgotten in #21327.

Commits
-------

9e33434 [DependencyInjection] Remove an unused docblock

src/Symfony/Component/DependencyInjection/Compiler/AutowirePass.php

@@ -24,9 +24,6 @@
  */
 class AutowirePass extends AbstractRecursivePass implements CompilerPassInterface
 {
-    /**
-     * @var ContainerBuilder
-     */
     private $reflectionClasses = array();
     private $definedTypes = array();
     private $types;