[R6RS] string escapes

[dyb at cs.indiana.edu]

> However, this makes it harder to adopt pointy brackets as regular
> general grouping syntax in R9RS, right?

I think that's already hopeless for R9RS.  There are two many symbols
in the world with > and < in their names, and we've authorized the
creation of even more by allowing symbols to start with ->.

> I would slightly prefer
>
> \xXXX...;
>         ^ delimiter
>
> in strings and
>
> #\xXXX (implicitly delimited)
>
> in characters.

This is okay with me, too.

Kent