The help text on shutdown should say that it creates a 'Content Violation Notice' room rather than just shutting down the room

[reivilibre]

Not thinking anything of it, I told someone that using the shutdown function of Mjolnir would be fine to 'close' a room, thinking it would just use the Synapse API.

The help text didn't mention this, but it created a new room called 'Content Violation Notice' and invited most of the users there and then told them off. That was not quite what we intended (related: #333).

This is a bit misleading from the command name, but worse is that I did actually read the help text and this wasn't mentioned at all. Ideally this would be mentioned in the help text :-)