Feat: Intent warning for events and prefixed commands

[Kigstn]

What type of pull request is this?

• Non-breaking code change
• Breaking code change
• Documentation change/addition
• Tests change

Description

This warns users if they use a gateway event / prefixed commands and do not have the required intents enabled. If users read their console output, this should make debugging easier for them.

Lists of intents and events taken from https://discord.com/developers/docs/topics/gateway#list-of-intents

Changes

• warn when event is missing required intent
• warn when prefixed commands are used but the message content intent is missing

Checklist

• I've formatted my code with Black
• I've ensured my code works on Python 3.10.x
• I've tested my code

[LordOfPolls]

I'd suggest using references to the event objects rather than strings. That way if we were to refactor they'd be caught by most modern IDEs

[Kigstn]

I'd suggest using references to the event objects rather than strings. That way if we were to refactor they'd be caught by most modern IDEs

Sure, good call

[AstreaTSS]

Too lazy to do a proper review, but it should be noted that prefixed commands will work fine even without the message content intent unless they change the prefixes used to outside of their defaults (you can always mention the bot). Probably worth checking for that.

[silasary]

Bonus points if you refactor all existing references to these to also use events., but I'm happy to merge without that