nullable_type_declaration_for_default_null_value should not fix readonly constructor promoted properties if set to false

[devmrcl]

Bug report

Rule

'nullable_type_declaration_for_default_null_value' => ['use_nullable_type_declaration' => false]

Description

Latest version 3.5 "fixes" readonly promoted properties with the given rule.
Rule should not touch the code like with non-readonly promoted properties.

Code snippet that reproduces the problem

class SomeClass
{
   public function __construct(
      public ?string $string = null,
      public readonly ?string $readonlyString = null,
   ){}
}

Diff output

public function __construct(
         public ?string $string = null,
-        public readonly ?string $readonlyString = null,
+        public readonly string $readonlyString = null,
)

Possible fix

Add check for T_READONLY

https://github.com/FriendsOfPHP/PHP-CS-Fixer/blob/333f15e07c866e33e2765e84ba1e0b88e6a3af3b/src/Fixer/FunctionNotation/NullableTypeDeclarationForDefaultNullValueFixer.php#L139-L152

[SpacePossum]

Thanks for reporting @devmrcl , proposed fix is here #6265 , please review if you want : )