Add support for the new username system

[starshine-sys]

Adds what is currently documented in discord/discord-api-docs#6130. The documentation isn't merged yet, but this has already started rolling out to normal users.

[diamondburned]

Is the GlobalName here the display name? AFAIK the new global username is kept the same in the Username field?

[starshine-sys]

Yeah, GlobalName is the display name--I'm pretty sure the field was originally called display_name but it got changed before the rollout.

[diamondburned]

I'm pretty sure the field was originally called display_name but it got changed before the rollout.

Is there a good reason for this? Should we call it DisplayName on our end (to match the client) or keep? Does Discord intend to eventually remove display names?

[starshine-sys]

I can't think of any good reason for it being changed other than maybe reducing confusion with server nicknames, so DisplayName is probably a better name for it, yeah. I doubt Discord will remove display names because it's prominently shown in the UI and mentioned in all their support articles.

[diamondburned]

Can you make the change? I'll approve the PR afterwards.

[diamondburned]

In hindsight, GlobalName would've been better, since that would allow a DisplayName() string method. I will add a DisplayOrUsername() string though.