[Feature request] Sticker detection

[JLyne]

Cog

• Defender
• Index
• Sbansync

Describe the feature you'd like to see
Now that stickers are rolling out more widely, and no sign of the promised permission controlling them, it would be nice if messages with stickers could be detected by Warden. A condition like message-has-sticker would do. A glance at the discord.py documentation suggests it should be a simple check for whether a message's stickers list is empty, so hopefully feasible to add.

Thanks for reading

[Twentysix26]

Blocked by Rapptz/discord.py#7140