bug#27270: display-raw-bytes-as-hex generates ambiguous output for Emacs strings

[Paul Eggert]

Eli Zaretskii wrote:
> Then maybe the new hex display should use the \N{U+nnn} format?

If we're going to do that, we might as well use \unnnn, which is shorter. A 
downside of either syntax, though, is the implication that the raw byte is 
intended to be Unicode, which it typically is not. That is partly why I was 
thinking \x{nn} would be better: it'd be clearer to users.