minor #32793 [Stopwatch] fix some phpdocs (Tobion)

This PR was merged into the 3.4 branch.

Discussion
----------

[Stopwatch] fix some phpdocs

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets |
| License       | MIT
| Doc PR        |

Fix phpdocs found in #32242

Commits
-------

66dc906 [Stopwatch] fix some phpdocs

src/Symfony/Component/HttpKernel/DataCollector/TimeDataCollector.php

@@ -15,10 +15,9 @@
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\KernelInterface;
 use Symfony\Component\Stopwatch\Stopwatch;
+use Symfony\Component\Stopwatch\StopwatchEvent;
 
 /**
- * TimeDataCollector.
- *
  * @author Fabien Potencier <fabien@symfony.com>
  */
 class TimeDataCollector extends DataCollector implements LateDataCollectorInterface
@@ -77,7 +76,7 @@ public function lateCollect()
     /**
      * Sets the request events.
      *
-     * @param array $events The request events
+     * @param StopwatchEvent[] $events The request events
      */
     public function setEvents(array $events)
     {
@@ -91,7 +90,7 @@ public function setEvents(array $events)
     /**
      * Gets the request events.
      *
-     * @return array The request events
+     * @return StopwatchEvent[] The request events
      */
     public function getEvents()
     {

src/Symfony/Component/Stopwatch/Section.php

@@ -67,6 +67,8 @@ public function get($id)
                 return $child;
             }
         }
+
+        return null;
     }
 
     /**
@@ -110,8 +112,8 @@ public function setId($id)
     /**
      * Starts an event.
      *
-     * @param string $name     The event name
-     * @param string $category The event category
+     * @param string      $name     The event name
+     * @param string|null $category The event category
      *
      * @return StopwatchEvent The event
      */