Fixes #312
Fixes #312

On some browsers (Chromium 83.0.4103.97 on Arch) a scrollbar
would appear on the outer side pane div. This is unneeded and
messes with the formatting of the child content. To fix it the
scrollbar is explicitly disabled in the CSS with overflow:hidden;

hazelgrove/hazel,hazelgrove/hazel,hazelgrove/hazel