Users wiki: stock-ssh quoting, --help over ssh, and the stale companion-wiki paragraph #204

Three fixes to .gitbay/wiki/Users.org:

• ssh git@gitbay.org repo create ttorg/widget --description "a widget" fails with unexpected argument "widget": ssh joins its arguments with spaces and the server tokenizes the result, so a multi-word value needs a second layer of quotes (--description "'a widget'"). The page says stock ssh "behaves identically"; it should say this.
• <cmd> --help over stock ssh is unknown flag; the form is help <noun>.
• The wiki section still describes companion <repo>.wiki repositories, which #170 removed; it should point at .gitbay/wiki/.

Ref #185