* Remove outline suppression for focused `<pre>`
Sighted keyboard users rely on knowing where their focus is. If the `<pre>` receives focus (so that it can be scrolled by keyboard users, for instance) then it's essential that they know this is the case
* Only suppress outline for buttons when `:not(:focus-visible)`
* Add right-hand margin to pre
avoids having the focus outline awkwardly clipped by the copy button