[Docs]: example for `union`

[gam6itko]

Describe the bug

I can't find union example. You should ad it!

something like this

$select = $this->db('prefixed', 'prefix_')
            ->select('*')
            ->from('table AS u')
            ->where('type', 'user')->orWhere('table.id', '<', 100);

        $select->union(
            $this->db('prefixed', 'prefix_2_')
                ->select('*')
                ->from('table AS u')
                ->where('type', 'admin')->orWhere('table.id', '>', 800)
        );

taken from here

To Reproduce

Try to search union here

https://cycle-orm.dev/docs/query-builder-complex/current/en

Media prove

No response

Describe the solution you would like

exmple for union

Additional context

No response