Support reduced type inferring from Collection::isEmpty about psalm-plugin-doctrine HOT 2 CLOSED

<?php
/**
 * @template TKey as array-key
 * @template TValue
 * @template-extends IteratorAggregate<TKey,TValue>
 * @template-extends ArrayAccess<TKey,TValue>
 */
interface Collection extends Countable, IteratorAggregate, ArrayAccess
{
    /**
     * @return TValue|false
     */
    public function first();
    
    /**
     * @return bool
     */
    public function isEmpty();
}

/** 
 * @param Collection<array-key, stdClass> $foo
 * @return stdClass
 */
function foo(Collection $foo): ?stdClass {
    if (!$foo->isEmpty()) {
        return $foo->first();
    }
    
    return null;
}