-x : ensure info hash is unique for easier cross-seeding

[nikolamakin]

If this parameter is enabled to seed, another hash will be displayed when the seed is opened on other clients. If this parameter is not used, the hash will always be unique.
Based on the above facts, I think it is necessary to explain the - x parameter in more detail. Avoid user ambiguity

eg:
mktorrent generation ..
magnet:?xt=urn:btih:efa8b1a37da52ae5fa7a711eb361bfab12ad72b4

qbittorrent is open torrent file show torrent hash:
magnet:?xt=urn:btih:1fa7f48c866cb6a9c90b314ad2d2148c3ac422f7

close -x
is hash same

[casey]

It looks like this was added in #48, and can probably be closed.

[pobrn]

@casey this was opened after the PR had been merged, I assume there's a problem with the feature.

@nikolamakin could you elaborate the issue?

[casey]

@pobrn Whoops, my mistake!