user.displayName does not account for the global display name

[Mireole]

The displayName user object returned by util.fetchUsers is wrong when the user has not set a custom nickname in the server.
If the user has set a server-specific nickname, displayName will correcly reflect it, but if this is not the case, it will return the user's username instead of his display name.

displayName should be Mireole but is mireole instead