bug#48225: Wrong result of package-name->name+version

[Guillaume Le Vaillant]

Hi,

The 'package-name->name+version' function defined in
"guix/build/utils.scm" returns a wrong result if there is a '-'
followed by a number in the package name:

--8<---------------cut here---------------start------------->8---
(use-modules ((guix build utils)))
(package-name->name+version "sbcl-3d-vectors-3.1.0-1.29bb968")

$1 = "sbcl"
$2 = "3d-vectors-3.1.0-1.29bb968"
--8<---------------cut here---------------end--------------->8---

It should be:

--8<---------------cut here---------------start------------->8---
$1 = "sbcl-3d-vectors"
$2 = "3.1.0-1.29bb968"
--8<---------------cut here---------------end--------------->8---

Can someone think of an elegant modification for
'package-name->name+version' so that it finds where the version is
even if there are several hyphens before of after it (as in
"sbcl-3d-vectors-3.1.0-1.29bb968" or "nyxt-2-pre-release-6")?

This is related to issue #48208, and also probably to issue #41437.