feat(voice): support resuming voice connection

[james58899]

https://discord.com/developers/docs/topics/voice-connections#resuming-voice-connection

The Discord voice gateway will disconnect with code 1006 after a period of time, but the UDP connection is still normal.
We can use Opcode 7 Resume to restore the websocket connection without affecting other states.
If use Opcode 0 Identify to reconnect the voice gateway will disconnect with code 4006.

[abalabahaha]

Need to test, but I think 1000 is still a normal close where reconnect isn't wanted, so === 1006 may fit better than < 4000

[james58899]

In discord.js it is code === 4_015 || code < 4_000¹, because discord usually uses 4014 to disconnect, but I only see 1006 in my test, so I think changing < 4000 to === 1006 is ok.

Footnotes

1. https://github.com/discordjs/discord.js/blob/dc142c47e4021d6d37712453cc2fad6e4fe4e9f7/packages/voice/src/networking/Networking.ts#L357 ↩