[bug#46865] [PATCH] gnu: racket: update to 8.0.

[Philip McGrath <philip@philipmcgrath.com>]

I changed the description primarily because, as of Racket 8.0, it is no 
longer accurate to say, "It features a compiler and a virtual machine 
with just-in-time native compilation"—the default implementation is now 
a native code compiler based on Chez Scheme.

But there's certainly still room for improvement. In particular, I see 
that Nix is using the description:

 > Racket is a full-spectrum programming language. It goes beyond
 > Lisp and Scheme with dialects that support objects, types,
 > laziness, and more. Racket enables programmers to link
 > components written in different dialects, and it empowers
 > programmers to create new, project-specific dialects. Racket's
 > libraries support applications from web servers and databases to
 > GUIs and charts.

The Racket project has used descriptions along those lines in other 
places before.

I left the synopsis, "Implementation of Scheme and related languages", 
alone, but that's also debatable. From a Racketeer's perspective,
Racket contains a Scheme implementation, but it is not primarily a 
Scheme implementation. Nix uses the short description, "A programmable 
programming language".