pin method
Pin a message in the channel.
Implementation
Future<void> pin(Snowflake id, {String? auditLogReason}) async {
final route = HttpRoute()
..channels(id: channelId.toString())
..pins(id: id.toString());
final request = BasicRequest(route, method: 'PUT', auditLogReason: auditLogReason);
await client.httpHandler.executeSafe(request);
}