Clarify comment on AoC Status Task startup delay

The Advent of Code Status Countdown task needs to wait for two things to
happen to prevent it from failing during the startup sequence:

1. The Websocket instance discord.py creates needs to be available as
   an attribute of the bot, otherwise discord.py fails internally:

Traceback (most recent call last):
  File "discord/client.py", line 1049, in change_presence
    await self.ws.change_presence(
      activity=activity, status=status, afk=afk
    )
  File "advent_of_code/_cog.py", line 52, in countdown_status
    await bot.change_presence(activity=discord.Game(playing))
AttributeError: 'NoneType' object has no attribute 'change_presence'

2. Allegedly, according to the discord.py community, trying to change
   the status too early in the sequence to establish a connection with
   Discord may result ub the Discord API aborting the connection.

To solve this, I've added a `wait_until_guild_available` waiter, as it
guarantees that the websocket is available and the connections is
mature.

Kaizen: I've changed the name `new_puzzle_announcement` to
`new_puzzle_notification` to better reflect its function.

0 files changed, 0 insertions, 0 deletions