[TASK] Use DiagramRenderer interface for decorator dependency

Change DecoratingPlantumlBinaryRenderer constructor to accept
DiagramRenderer interface instead of concrete PlantumlRenderer.

This improves testability and follows dependency inversion principle.
The decorator only needs the interface contract, not the concrete
implementation.

Relates: TYPO3-Documentation#1099

Author: CybotTM

packages/typo3-docs-theme/src/Renderer/DecoratingPlantumlBinaryRenderer.php

@@ -5,7 +5,6 @@
 namespace T3Docs\Typo3DocsTheme\Renderer;
 
 use phpDocumentor\Guides\Graphs\Renderer\DiagramRenderer;
-use phpDocumentor\Guides\Graphs\Renderer\PlantumlRenderer;
 use phpDocumentor\Guides\RenderContext;
 
 use function is_dir;
@@ -24,7 +23,7 @@ final class DecoratingPlantumlBinaryRenderer implements DiagramRenderer
 {
     private const TEMP_SUBDIRECTORY = '/phpdocumentor';
 
-    public function __construct(private readonly PlantumlRenderer $innerRenderer) {}
+    public function __construct(private readonly DiagramRenderer $innerRenderer) {}
 
     public function render(RenderContext $renderContext, string $diagram): string|null
     {