Lists are convenient to have in sysupdate configuration when using
multiple `MatchPattern` under `Target` when the target can have multiple
filenames. This use-case is helpful for BootLoaderSpec bootcounting where the target file on
disk can have multiple filenames, and in order for sysupdate to properly
ensure only N number of instances of this target exist at one time, we
need to have multiple match patterns.
The example systemd-sysupdate transfer name has a ".conf" suffix,
although the files on the final system are already appended with this
suffix, so the file ends up being "transfer-name.conf.conf". Remove the
suffix in the example so that users will get a transfer filename they
expect.
