Hi there! I've got some commands set up for the bridge including the !kill <> which relays to the /kill <> command, but I'd like a way to be able to prevent the feedback from appearing in the channel.

I'd like to keep command feedback from different commands though. Just /kill @e[type=item] gets super spammy and the bot gets throttled deeply by Discord itself.

This should do the work.
I tested it with a new local instance, I registered a few commands with and without the new flag and it worked flawless.
After further testing I'll create a PR (or two, in this case).

@chikachi can you have a look at the two commits whether the changes are OK for you?

@Mijago LGTM