The `imdl torrent show` command displays information about on-disk
torrent files. The formatting of the command's output is copied from
torf, an excellent command-line torrent creator, editor, and viewer.
type: added
- Must be greater than zero
- Must be a power of two (but can override with `--allow uneven-piece-length`
- Must be greater than 16KiB (but can override with `--allow small-piece-length`
- Must be less than u32 max
type: changed
