doc: put release script specifics in details

Listing all the steps can be confusing an make it seem like
the releaser is meant to run each of these steps manually. In fact
I personally did that my first release.

Let's put those steps in a details block to make it more obvious
that it is informational and not steps to follow

PR-URL: #35260
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ruy Adorno <ruyadorno@github.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

doc/guides/releases.md

@@ -598,6 +598,8 @@ $ ./tools/release.sh -i ~/.ssh/node_id_rsa
 
 `tools/release.sh` will perform the following actions when run:
 
+<details>
+
 **a.** Select a GPG key from your private keys. It will use a command similar
 to: `gpg --list-secret-keys` to list your keys. If you don't have any keys, it
 will bail. If you have only one key, it will use that. If you have more than
@@ -631,6 +633,7 @@ SHASUMS256.txt.sig.
 
 **g.** Upload the `SHASUMS256.txt` files back to the server into the release
 directory.
+</details>
 
 If you didn't wait for ARM builds in the previous step before promoting the
 release, you should re-run `tools/release.sh` after the ARM builds have