chore(Threads): general fixup and catch up on features

[ckohen]

Please describe the changes this PR makes and why it should be merged:

Fixes included:

• Typings and docs corrections for GuildChannelManager, oversight from feat: api v9 and threads #5570
• Docs example for thread creation made more clear
• Fixes subtle bug with GuildChannelManager#resolve due to ThreadChannels not actually extending GuildChannel
• Changes GuildMember#permissionsIn to use channel.permissionsFor instead of channel.memberPermissions as TreadChannels do not have this method and it is "private"

Catchup:

• Add new guild features for threads and necessary warnings
• Add new API Error that comes with boost locked thread features

This is unfortunately necessary 😢
I'm making the breaking change to ThreadManager#create that will probably be made to the API in its next version.

Status and versioning classification:

• Code changes have been tested against the Discord API, or there are no code changes
• I know how to update typings and have done so, or typings don't need updating
• This PR includes breaking changes (methods removed or renamed, parameters moved or removed)

[iShibi]

While you are at it, could you fix the description for thread channel types here. It should be like this for all three of them:

- `news_thread` - a guild news channels' public thread channel
+ `news_thread` - a guild news channel's public thread channel