ui: Fix the "Next chapter" link position

[WofWca]

Remove the gap between it and the right edge of the page.

Demo: https://wofwca.github.io/mdBook/format/config.html

This reverts f1cd9f5 (That fixed /rust-lang/book/issues/29)
The page layout has been restructured and this workaround is no
longer required

[WofWca]

I don't think that my changes are the cause of the build failure.

[ehuss]

I don't think that my changes are the cause of the build failure.

Looks like an issue due to mozilla/sccache#488. cc @lzutao

[ehuss]

Hm, so in testing this out this seems to cause some issues on firefox and chrome. If the scroll bar is not displayed, this prevents the scroll bar from appearing when the cursor is positioned over it. You have to scroll a little bit to get it to appear, and then you can interact with it. It seems a little awkward. Is there something in particular this is trying to improve or fix?

[WofWca]

Could you please provide more details on how to reproduce this? I've played around a bit and couldn't seem to experience this.

Is there something in particular this is trying to improve or fix?

Yes.
Sometimes you miss the button by clicking right on this gap, especially when there's no scrollbar and you just move the cursor right to the edge of the screen.
Also with the #994 change, this should make it look better (remove the gap).

[ehuss]

Hm, maybe it is unique to Firefox on macos. Firefox auto-hides the scroll bar, and you end up with this situation:

Clicking in this region goes to the next page instead of scrolling.

What's weird is that on safari and chrome, the scroll bar never auto-hides. That's not normal, so I guess it is related to some of the scrollbar css settings?