[css-color-4] Update the system color pairings with the new system colors

[andreubotella]

Issue #4924 added the new system colors Mark, MarkText and ButtonBorder, but it didn't update the system color pairings to include them. "Mark background with MarkText foreground" is an obvious addition, but the color combinations for ButtonBorder would need more than that.

If I'm reading "Understanding WCAG" correctly, the following adjacent color contrasts would be needed:

• A ButtonFace or Field background with a ButtonBorder border and adjacent color Canvas.
• A Canvas background with a ButtonBorder border and adjacent color Canvas (since it was mentioned in [css-color][css-color-adjust] We should add sufficient system colors to fully implement the HTML UA stylesheet #4924 that ButtonBorder could also be used for styling <hr /> elements).

And Highlight and Mark might also be added as alternatives to Canvas for those contrasts.

[svgeesus]

Thanks for the report, now fixed