New partition() collection method

[techmahedy]

Split the collection into two groups based on a condition. Returns [passed, failed]

Example usages:

// Separate active and inactive users
[$active, $inactive] = $users->partition(fn($user) => $user['active']);

// Split passing and failing grades
[$passed, $failed] = $grades->partition(fn($grade) => $grade >= 60);

// Separate in-stock and out-of-stock items
[$inStock, $outOfStock] = $products->partition(
    fn($p) => $p['quantity'] > 0
);