Nicer formatting for console output in docs

[flaki]

A really cool trick some docs sites employ is when they show a terminal command and its output they make the command itself selectable (and highlighted, even), while the passive output and terminal prompt is disabled/unselectable and faded out to make it clearer what's the actual command that is being run and what is the expected output.

We should consider implementing something like this (ideally besides the usual "copy" button).