A ExGram.BotInit hook that registers the bot's commands with Telegram at
startup.
This hook is automatically injected by the dispatcher when
setup_commands: true is given to use ExGram.Bot or when starting the
bot:
{MyBot, [method: :polling, token: token, setup_commands: true]}It delegates to ExGram.Bot.SetupCommands.setup/2, which calls
setMyCommands for each declared command scope/language combination.
The hook expects a bot_module key in the hook opts, which the dispatcher
injects automatically. It reads bot_module.commands() to get the full
command definitions.