release: Release with separate SHA256SUMS and sig files

This allows us to remove the rfc4880 EOL hacks and release with a
SHA256SUMS.asc file that's a combination of all signer signatures.

doc/release-process.md

@@ -199,26 +199,13 @@ popd
 
 ### After 3 or more people have guix-built and their results match:
 
-Combine `all.SHA256SUMS` and `all.SHA256SUMS.asc` into a clear-signed
-`SHA256SUMS.asc` message:
-
-```sh
-echo -e "-----BEGIN PGP SIGNED MESSAGE-----\nHash: SHA256\n\n$(cat all.SHA256SUMS)\n$(cat filename.txt.asc)" > SHA256SUMS.asc
-```
-
-Here's an equivalent, more readable command if you're confident that you won't
-mess up whitespaces when copy-pasting:
+Combine the `all.SHA256SUMS.asc` file from all signers into `SHA256SUMS.asc`:
 
 ```bash
-cat << EOF > SHA256SUMS.asc
------BEGIN PGP SIGNED MESSAGE-----
-Hash: SHA256
-
-$(cat all.SHA256SUMS)
-$(cat all.SHA256SUMS.asc)
-EOF
+cat "$VERSION"/*/all.SHA256SUMS.asc > SHA256SUMS.asc
 ```
 
+
 - Upload to the bitcoincore.org server (`/var/www/bin/bitcoin-core-${VERSION}`):
     1. The contents of `./bitcoin/guix-build-${VERSION}/output`, except for
        `*-debug*` files.
@@ -230,7 +217,9 @@ EOF
        as save storage space *do not upload these to the bitcoincore.org server,
        nor put them in the torrent*.
 
-    2. The combined clear-signed message you just created `SHA256SUMS.asc`
+    2. The `SHA256SUMS` file
+
+    3. The `SHA256SUMS.asc` combined signature file you just created
 
 - Create a torrent of the `/var/www/bin/bitcoin-core-${VERSION}` directory such
   that at the top level there is only one file: the `bitcoin-core-${VERSION}`