[Deprecation] Deprecate TemplateAnnotationToThisRenderRector as risky, annotation based and better tailored to the project

[TomasVotruba]

TemplateAnnotationToThisRenderRector turns a @Template/#[Template] annotation into an explicit $this->render() call. To do that it has to answer two questions that only the project itself can answer.

1) Where does the template live? The rule guesses the path from bundle and controller naming conventions:

 final class SomeController
 {
-    /**
-     * @Template()
-     */
     public function indexAction()
     {
+        return $this->render('index.html.twig');
     }
 }

The 'index.html.twig' is derived from the class name, namespace and an optional bundle lookup. Any project that does not follow the conventions the guesser assumes gets a path to a template that does not exist, and the breakage only shows up at runtime.

2) Is this return template variables, or an already built Response? The rule inspects the return type of every return statement and rewrites only those it believes carry template variables:

 public function detailAction()
 {
     if ($this->isGranted('ROLE_ADMIN')) {
-        return ['key' => 'value'];
+        return $this->render('detail.html.twig', ['key' => 'value']);
     }

     return new RedirectResponse('/');
 }

When the inferred type is a union, mixed, or comes back from a method call the rule cannot resolve, the classification is a guess. Guessing wrong either drops the render call or wraps a Response in another Response.

Both questions are answerable inside one codebase and not in general. A local custom rule can hardcode the template path convention and the return shapes that actually occur, which is both simpler and safe.

The rule is registered in no set, so it can only be reached by hand-registering it.

Changes

• TemplateAnnotationToThisRenderRector implements DeprecatedInterface and throws on refactor(), matching the existing deprecation pattern
• Removes the helper classes the rule was the only consumer of: ThisRenderFactory, TemplateGuesser, BundleClassResolver, ArrayUnionResponseTypeAnalyzer, ReturnTypeDeclarationUpdater, EmptyReturnNodeFinder, AnnotationAnalyzer, AnnotationOrAttributeValueResolver, ArrayFromCompactFactory
• Removes SymfonyAnnotation::TEMPLATE, unused once the rule stops resolving the annotation
• Removes the rule test suite and its 37 fixtures