[DOCS] Use correct variable in code example in `ext:dashboard`

This change use the correct variable to assign view
variables in one example in WidgetImplementation.rst.

Releases: main, 12.4
Resolves: #102318
Change-Id: I601d2589ec3a44ab77d8548d507b20969d4e11b2
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/81688


Tested-by: Andreas Kienast <a.fernandez@scripting-base.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Andreas Kienast <a.fernandez@scripting-base.de>

typo3/sysext/dashboard/Documentation/Developer/WidgetImplementation.rst

@@ -53,13 +53,13 @@ This class has to implement the :php:class:`WidgetInterface` and could look like
         public function renderWidgetContent(): string
         {
             $view = $this->backendViewFactory->create($this->request);
-            $this->view->assignMultiple([
+            $view->assignMultiple([
                 'items' => $this->getRssItems(),
                 'options' => $this->options,
                 'button' => $this->getButton(),
                 'configuration' => $this->configuration,
             ]);
-            return $this->view->render('Widget/RssWidget');
+            return $view->render('Widget/RssWidget');
         }
 
         protected function getRssItems(): array