New features

• New endpoints to support publishing crossposts in announcement channels.
• BotAware.run and BotAware.start are now required to expose some kwargs
  provided in BotApp as part of the interface.
• Windows signal handling stuff (see below).
• New logging logger level can be used. Use "TRACE_HIKARI" to view
  the majority of what was in the "DEBUG" level logs before (namely
  request payloads, etc). This should now allow developers to add stuff to
  the "DEBUG" logs and not be assaulted with socket packet data as soon as
  they turn debug logs on. Debug logs are now much more readable.

Stuff to help new developers out

• Using with <thing> instead of async with <thing> on objects made by
  hikari that require async with will now suggest how to fix this issue in the
  error message (foo.Bar is async-only, did you mean 'async with'?).

Renaming

• Private channels are now known as DM channels again, to match the API
  naming.

Fixes and optimisations

• Speedups for entity rebuilding in cache
• TCP connector bugfixes for Windows. You should hopefully not get
  NoneType is not a socket errors or similar when aiohttp/asyncio
  encounters issues with the TCP/IP stack on Windows now. Hopefully.
• Rewritten signal handling logic to work differently. Bots on Windows
  should now support closing gracefully when you use a keyboard interrupt
  (PyCharm will still just murder the process immediately, though).
• Bot.close has been reimplemented (see below).
• Fixed bug where closing bot during shard startup would take up to 5
  seconds to begin to be processed. Shards are interrupted immediately
  now.
• RESTApp's _RESTProvider is now fully implemented again and shouldn't
  throw abstract class initialization errors when used internally, meaning the
  REST only client should work again.
• Closing the bot now waits for shards to close properly. This was due to a
  regression in the logic from when we recently rewrote this mechanism which
  meant the shard was requested to close, but may not have shut down before
  the event loop got closed forcefully.
• Platforms that hang on socket IO when a shard zombies or the network
  goes down should now not wait forever.
• More contextual logging for why shards closed down specifically.
• If one shard is manually closed directly on startup, the bot should now see
  this and treat it as a failed startup rather than ignoring it.
• Ping-pong heartbeating is now disabled.

Removed features

• Bot.terminate (was only added recently but is no longer needed due to
  the other aforementioned changes).
• debug kwarg in components. Use the TRACE_HIKARI logging level
  instead.
• version kwarg has been removed from BotApp, RESTApp, RESTClientImpl,
  and GatewayShardImpl.
• UnavailableGuild no longer exists. Guilds that become unavailable are simply
  marked as being in this state. READY guilds are not cached until they become
  available for the first time.