Fixing lists for VoiceOver 🤦🏻‍♀️

See here:

* https://www.scottohara.me/blog/2019/01/12/lists-and-safari.html
* https://unfetteredthoughts.net/2017/09/26/voiceover-and-list-style-type-none
* https://twitter.com/yatil/status/1083736641737502720

I really don't like this and agree 100% with this [tweet](https://twitter.com/yatil/status/1083738608593448963). But caring about accessibility I feel my hands are tied.

Here is the related code:

https://github.com/chris-pearce/backpack.css/blob/318df58e7d9c84817bdf20f8b4e8666e0a7b27aa/src/text-content.css#L1-L10

Start with src/text-content.css lines 1–10 and read the three linked articles about VoiceOver, Safari, and list-style behavior. Clarify the intended accessible list treatment before changing anything; done means the CSS addresses the reported VoiceOver problem without losing the desired list presentation.

Written by the indexing model from the issue text.