login/token: remove misleading comment about LoadUserLogin

This comment seems to imply that specifying this function is a shortcut
of sorts, when it's actually required and mautrix-go doesn't fallback to
the connector in the way described.

pkg/connector/login_token.go

@@ -101,8 +101,6 @@ func (dl *DiscordTokenLogin) SubmitUserInput(ctx context.Context, input map[stri
 			HeartbeatSession: session.HeartbeatSession,
 		},
 	}, &bridgev2.NewLoginParams{
-		// We already have a Session; let's call this instead of the connector's
-		// main LoadUserLogin method, and thread the Session through.
 		LoadUserLogin: func(ctx context.Context, login *bridgev2.UserLogin) error {
 			login.Client = &client
 			client.UserLogin = login