Handle class-string type in StrictTypeFromDocTypeFactory

[BinaryKitten]

This adds support for class-string usage in the tag converting to string return/var type

This prevents this from happening

-     * @var class-string<\Illuminate\Database\Eloquent\Model>
+     * @var class-string<Model>
      */
-    protected $model = InvoiceItem::class;
+    protected class-string<Illuminate\Database\Eloquent\Model> $model = InvoiceItem::class;

and instead generates

-     * @var class-string<\Illuminate\Database\Eloquent\Model>
+     * @var class-string<Model>
      */
-    protected $model = InvoiceItem::class;
+    protected string $model = InvoiceItem::class;