v6: Safari bugs on older versions

[coliff]

Was just testing the v6 Cheatsheet page using older versions of Safari on BrowserStack and noticed a few things. (non exhaustive - will dig deeper)

• Tooltips and Popovers crashing on macOS 17.3 and older

• Dialogs crashing on close

• backdrop-filter blur on modals / drawers not displaying

• Lots of issues with colors on macOS 15.6 - this browser is super old, suggest considering dropping support for it.

Fixed Issues

- Accordions show the disclosure triangle on macOS 17.3 and older (FIXED!)

[coliff]

ah, for the accordions we need to add CSS:

&::-webkit-details-marker {
  display: none;
}

Made a PR: #42401