Just added in multiple=>'multiple' since it's a common thing to want with a select. It makes it a bit more obvious that all extra parameters are translated to attributes too.
Small change to highlight the %attributes
To me it looks like the proposed change would do the opposite of what it's intended to do, all other examples consistently use id as random attribute to be passed through. I'm generally in favor of making that behavior more obvious, but it should be consistent for all tag helpers. The patch also doesn't follow our formatting rules and the example output is incorrect.