[popover] add polyfill support for :popover-open

[eloyesp]

Currently on v4-beta8, the class open:visible is transformed on the following css:

.open\:visible {
  &:is([open], :popover-open) {
    visibility: visible;
  }
}

I would use this instead to make it compatible with a still required polyfill.

.open\:visible {
  &:is([open], :popover-open, .\:popover-open) {
    visibility: visible;
  }
}

I'm not sure if there is a better place to add this change than on tailwind itself, or how easy would be to fix that on the config.