Ping devs when `!override` is used

[TimJentzsch]

Using !override is really bad for us as it can mess up the data and is always only a temporary fix.

Using it should ping the devs and the mod who used the command to make it as noisy and annoying as possible.

If feasible, it should contain the following information:

• The mod who used !override
• The volunteer whose submission was overridden
• The source of the transcription