feat(Guild): allow description and features in edit

[almostSouji]

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

• Guild#edit now allows modification of features (COMMUNITY, to enable community features)
• Guild#edit now allows the discovery description to be modified

as per discord/discord-api-docs#1764

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 changes the library's interface (methods or parameters added)

[SpaceEEC]

I'm unable to set a description (just silently fails on Discord's end), probably due to not being on discovery.

Further enabling community only works when the payload also includes a rules and public updates channel (does not matter if you previously set them).
Otherwise you are getting the very helpful and totally not misleading error This feature has been temporarily disabled (The code is 40006, if somebody is interested).

I don't think there is much we can do about either though.

stale