Allow deletion of bot messages by reacting with :wastebasket:

[SkyTheCodeMaster]

This adds an on_raw_reaction_add event that:

• Checks if the message author is the the bot
• Checks if the reacted emote is a wastebasket If both of those conditions are true, it calls await message.delete() on the message, leading to it's deletion. This is a good change because it will allow people to delete the output of things like %eval without requiring staff assistance, which will declutter chats like #computercraft.

[SkyTheCodeMaster]

If someone wants this limited to only %eval output, you could add if message.attachments: to the check for deletion. Empty lists (no attachments) are falsey in Python, so it would not let the message be deleted.

[Wojbie]

It probably should only be limited to only if original %eval caller or moderator reacts with 🗑️

EDIT: Or if like 5 unique people reacted with 🗑️ too. So other people could trigger it via mini-agreement.

[SkyTheCodeMaster]

The bot replies to the original message, so it should be possible to have it only be with the original caller, check something like payload.user == message.reference.resolved.author? Then also do a check if a person reacting has a role named "Moderator", or a specific permission, like Manage Messages?

[SkyTheCodeMaster]

The reason I originally had it as on_raw_reaction_add is because when programming my own bot, I found that without the raw event, it only retrieved reactions on messages that were sent after the bot started, whereas the raw event received reactions from messages before the bot started.