[Formatter] Add a new line before the arrow (`=>`) of short anonymous functions

[gnutix]

🚀 Describe the Feature

Hello!

This is probably personal, but I like to write anonymous functions like this and find it more readable :

$shortLine = static fn (string $arg, bool $arg2): string => $arg2 ? $arg : '';
$longLine  = static fn (string $arg, bool $arg2): string
    => self::someVeryLongMethodLine($arg) ? 'Do something with ' . $arg : $arg2;

Currently, mago lets the arrow "=>" on the same line as the function definition, and sometimes even starts the body's code on that line before cutting it in weird places, example :

static fn (UserRepository $repository): QueryBuilder => $repository->createQueryBuilder(
    'u',
)->orderBy('u.name', 'ASC'),

I would rather have :

static fn (UserRepository $repository): QueryBuilder
    => $repository->createQueryBuilder('u')->orderBy('u.name', 'ASC'),

or even :

```php
static fn (UserRepository $repository): QueryBuilder
    => $repository
        ->createQueryBuilder('u')
        ->orderBy('u.name', 'ASC'),

✅ Use Case / Example

I use a lot of functional patterns in my projects.

💡 Proposed Solution

Add a new rule empty-line-before-arrow-short-anonymous-function ?

📌 Priority

Not urgent, just an idea

📝 Additional Context

No response