remove -webkit-text-decoration-skip override

[antons]

normalize.css introduced -webkit-text-decoration-skip: objects for the sake of consistency. I propose to revert it, because:

1. It breaks iOS and macOS platform conventions: underlines are always drawn with “ink” style in native text views.
2. It’s a step back for web typography. Apple intentionally set the browser default to “ink” to make underlined text more readable.
3. The lack of this rule doesn’t affect other browsers, but its presence is harmful.

@broccolini mentioned that GitHub uses a fork of normalize.css. I originaly noticed the issue on GitHub, and it’s where I hope to see it reverted the most.

[broccolini]

Thanks for the pr @antons! We'll need to test this in GitHub first before pulling into a primer release, we'll comment back here as to how that goes.