Fix man and commandline docs

- missing help option in `docs/reference/commandline/*.md` (some files
  have it, the other I fixed didn't)
- missing `[OPTIONS]` in Usage description
- missing options
- formatting
- start/stop idempotence

Signed-off-by: Antonio Murdaca <amurdaca@redhat.com>

docs/reference/commandline/load.md

@@ -15,6 +15,7 @@ weight=1
 
     Load an image from a tar archive or STDIN
 
+      --help=false       Print usage
       -i, --input=""     Read from a tar archive file, instead of STDIN. The tarball may be compressed with gzip, bzip, or xz
 
 Loads a tarred repository from a file or the standard input stream.