CSS :has documentation shows wrong Firefox browser compatibility

# Documentation style bug

## Summary
shows the wrong browser compatibility for Firefox. It shows that the pseudo-selector works in Firefox, but it actually has only partial functionality (due to currently incomplete/buggy implementation) and is gated behind a feature flag. (see MDN screenshot below for reference)

## Actual style

## Expected style
(cell style changed from `.bc-supports-yes` to `.bc-supports-partial`)