main/alpine-base: Tweak /etc/issue to avoid incorrect English

Currently the message displayed above the login prompt on virtual
consoles looks like this:

  Welcome to Alpine Linux 3.21
  Kernel 6.12.8-0-virt on an x86_64 (/dev/ttyS0)

The "on an $arch" part results in correct English for some of
the supported architectures (e.g. x86_64 and aarch64) but not
for some others (e.g. riscv64 and loongarch64).

Tweak the message so that correct English is produced regardless
of the architecture.

Signed-off-by: Andrea Bolognani <eof@kiyuko.org>

main/alpine-base/APKBUILD

@@ -1,7 +1,7 @@
 # Maintainer: Natanael Copa <ncopa@alpinelinux.org>
 pkgname=alpine-base
 pkgver=3.22.0_alpha20250108
-pkgrel=0
+pkgrel=1
 pkgdesc="Meta package for minimal alpine base"
 url="https://alpinelinux.org"
 arch="noarch"
@@ -45,7 +45,7 @@ release() {
 	# create /etc/issue
 	cat >"$subpkgdir"/etc/issue<<EOF
 Welcome to Alpine Linux $_ver
-Kernel \\r on an \\m (\\l)
+Kernel \\r on \\m (\\l)
 
 EOF