So I was exporting an Org doc to html the other day, and I was trying to
follow this guide to make the list elements appear as a comma-separated list

https://markheath.net/post/css-comma-separated-list

It didn't work, and I discovered this was because Org adds a <br> element
to the <li> element if the <li> element is created from an Org headline
element. The easiest way to fix this and allow the aforementioned guide to
work is by ensuring that all those <br> elements have `display: none` set
via CSS. To make this easier and/or reduce the risk of accidentally
removing other elements, we can add a class name to those <br>'s the way we
do to other elements.

I have included an example change. This is just the simplest possible
solution. Obviously if someone thinks a more complicated/featureful
solution is required, we can do more stuff.

--dmr