Distinguish between the repeated text of remove-section buttons in Layout Builder UI

We don't need the span.visually-hidden here for the section number, because the entire text "remove section" is already visually hidden by .layout-section .remove-section { text-indent: -9999px; }.

Unless there's a problem from those two conflicting,

There isn't a conflict, it's just overkill to hide something, then hide it again. I thought this was excess code that could do with being tidied up. Patch #3 is safe. Happy to say RTBC.

That's a design choice which could always change. [...] the whole thing happening to be hidden for now

Are we planning to change it? A visible text label has several benefits over an icon only, but we can do that in a follow-up.

The problem addressed in this issue is: make the purpose clear to screen reader users who don't perceive the visual/spatial relationship of the button to the section.

I'd rather be clear about which part should always be visually hidden

Ah, now there's a misconception. Basically, that's framing it the wrong way around. There's no part of the accessible name which "should always" be visually hidden. Anyone can benefit from the whole name.

Visually hidden text is a common accessibility practice, but it's not a desirable thing in it's own right. Rather, it's an awkward compromise to meet the needs of screen reader users, while aiming for brevity in the visual UI design. Done badly, it can make things worse for speech control users, and it can somtimes pose challenges for translators too. If you can satisfy the needs of screen reader users without resorting to visually hidden text, so much the better.