Include @ username tags on responses in channels

[johndotpub]

If two different users send @bot messages in the same channel the replies will sometimes come in immediately following one another and it's not clear which is which.

AC:

• Each reply should include the @username for the Discord user that is being replied to.

[johndotpub]

NOTE: This will be problematic if the user asks the bot to tell someone else something... so there will need to be some form of check otherwise the response won't read properly.