Add more Twig blocks to the block--fences.html.twig

Very good idea! Are there any defaults for the block names we (can or already) stick to?
One introduced, that will be nearly impossible to change.

From the core blocks or olivero or other areas?

The old code already comes from Olivero, so no, not really. I would like eg. title_wrapper and title over title and title_inner, but we need to leave block "content" as it is, thats why I've choosed "foo_inner" instead, to have it equal.

Ok, I'm not the one to judge that :) So if it's fine for you and matching standards, feel free to merge it.

Should @Grevil add any tests?

Automatically closed - issue fixed for 2 weeks with no activity.