Ignore or handle webhooks (such as Pluralkit)

[OvercastWarmth]

As the title says. Current behaviour when a user with PluralKit requests a note is for the note to be posted twice. Once for the primary message, and then another time for the proxied message. This is very obviously unintentional behaviour, it should only be posted once.

Possible solutions I can think of:

• Ignore all webhooks when looking for text commands. This is probably the easiest option. The only issue is if the bot is too slow to be able to catch the primary message before it gets deleted, Discord will likely reject the message due to the reply pointing to a now dead message.
• Delete notes if the message requesting them has been deleted. This would also help with people who posted a note but wants to retract the message, but in the case of use with PluralKit will make the chat bounce even more with a larger message getting posted and subsequently deleted.
• Allow users to blacklist themselves from being able to use chat commands. Granted, this is a bit of a band-aid solution, but assuming that the user can disable note posting independently of webhooks this would also work as a solution, albeit a manual one on the user's end.

[mazziechai]

Kord Extensions actually has PluralKit integration to prevent doubleposting, so I can just set that up instead of rolling my own solution. Thanks for the report!