Replace copilotDisplayName with actorDisplayName(typeName, login, name)
which handles all actor types: known bots get friendly names (e.g.
Copilot → 'Copilot (AI)'), regular bots return login, users with
names return 'login (Name)', others return login.
All DisplayName() methods on Author, CommentAuthor, GitHubUser,
AssignableUser, AssignableBot, RequestedReviewer, and ReviewerBot
now delegate to actorDisplayName with their available fields.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
7198d270b4