[Symfony 7.3] Restore merged AsTwig attribute rules as deprecated

[TomasVotruba]

PR #1027 merged GetFiltersToAsTwigFilterAttributeRector and GetFunctionsToAsTwigFunctionAttributeRector into a single GetFiltersAndFunctionsToAsTwigAttributeRector, but removed the old classes outright. Anyone referencing them in their own rector.php gets a hard "class not found" crash with no hint where the rule went.

This restores both classes as deprecated stubs that point to the replacement.

What the deprecated rule does

Running either of the old rules now fails fast with a pointer:

"Rector\Symfony\Symfony73\Rector\Class_\GetFiltersToAsTwigFilterAttributeRector" is deprecated,
as it converts getFilters() only and leaves getFunctions()/getTests() behind.
Use "Rector\Symfony\Symfony73\Rector\Class_\GetFiltersAndFunctionsToAsTwigAttributeRector" instead.

Why they were merged

Converting one get*() method in isolation leaves a half-converted extension behind:

 use Twig\Extension\AbstractExtension;
+use Twig\Attribute\AsTwigFilter;

 class SomeExtension extends AbstractExtension
 {
-    public function getFilters()
-    {
-        return [new TwigFilter('filter_name', [$this, 'someFilter'])];
-    }
-
     public function getFunctions()
     {
         return [new TwigFunction('function_name', [$this, 'someFunction'])];
     }

+    #[AsTwigFilter('filter_name')]
     public function someFilter($value)
     {
         return $value;
     }
 }

The merged rule converts filters, functions and tests in one pass instead.

Notes

• Follows the same deprecation shape as the SwiftMailer rules in [SwiftMailer] Deprecate SwiftMailer to Symfony Mailer set #1026 — DeprecatedInterface + ShouldNotHappenException in refactor().
• Not re-registered in any set; composer-based.php keeps the merged rule only.