Don't split INSERT INTO SELECT into two statements

[^\\\")] merits a comment. It's got me stumped.
What I am expecting and not seeing here is an optional repeating group of comma plus identifier with liberal optional whitespace all around.
Either that OR something that will match anything but a ')' .
Technically it would want to match anything but a ')' that is not embedded in a quoted identifier, but I'm willing to forgive that edge case.