restic check: improve output / output recommendation

[scoddy]

fsck scans the repository (--check-data and --orphaned for full scan) but does not output useful information. E.g.:

./restic -r /mnt/usb/backup fsck --check-data
Enter Password for Repository: 
wrong data returned by backend, checksum does not match
wrong data returned by backend, checksum does not match
wrong data returned by backend, checksum does not match
wrong data returned by backend, checksum does not match
wrong data returned by backend, checksum does not match
wrong data returned by backend, checksum does not match
wrong data returned by backend, checksum does not match

Improve output and provide recommendation for the user to repair the repository (e.g. delete snapshot, redo backup, etc.).

[fd0]

Closing this for now, fsck was replaced by check.