docs: update required permissions for prune

[vcokltfre]

Summary

Update the documentation to reflect discord/discord-api-docs#6685

This is a single-word docs-only change, no code has been updated, so testing/etc have been skipped.

[vcokltfre]

Draft as the docs change isn't solidified yet, but when it is this can be merged.

[mezotv]

Discord just reverted this after the commit :kekw:

[mezotv]

Purge would then require the MANAGE_GUILD and KICK_MEMBERS permissions. Might be good to include both ig?

[mezotv]

New pull request regarding this API change

[shiftinv]

this one should be ready to go now, I believe?

[mezotv]

this one should be ready to go now, I believe?

Yep, should be ready to be merged now!

[Victorsitou]

Perhaps it would also be a good idea to update the documentation of Guild.estimate_pruned_members and add the required permissions to use it

[shiftinv]

Perhaps it would also be a good idea to update the documentation of Guild.estimate_pruned_members and add the required permissions to use it

It links to prune_members already, so this should be fine to leave as-is for now