Highlight add now requires Manage Messages permission

[zinabat]

The highlight command used to work for all regular members. It now requires the Manage Messages permission, which seems incorrect. This has broken the functionality for users who wish to use the highlights feature except for moderators/staff members.

Example

[devargon]

This repo hasn't been maintained in 2 years lol

[CarlGroth]

Yeah it's ridiculous. I don't run the bot anymore but this change is just because the people who took over couldn't scale the feature (hint: it's called aho-corasick)