Fix documentations that were incorrect or missing (#1837)

* Fix docs for Guild#pruneMembers

* ClientApplication returns

* Guild#deleteEmoji

* Guild#setRolePosition takes RoleResolvable

* Client#fetchApplication returns ClientApplication not Oauth2Application

* ClientDataResolver#resolveImage can return null

* ClientApplication#toString small example

* Guild#allowDMs now has a only for user accounts warning

* ClientUserSettings#patch is private and setGuildPosition has a user account warning

* Role#setPermissions can take PermissionResolvable, not just String

* ChannelCreationOverwrites is for a role or a member, not for a "group"

* Fix ChannelData#userlimit string being wrong
"The user limit of voice the channel" :lul:

* ChannelResolvable is only for Channel or Snowflake

* EmojiIdentifierResolvable supports Snowflakes

* UserResolvable doesn't take a guild

* Make patch functions private

* Remove examples

* Webhoox#edit options.name defaults to the webhook name

* Make VoiceConnection functions private

* Am dum
The whole ClientUserSettings category is only for self bots soo

* Value for update functions is *

* Make update functions be private

* Fix GuildEditData missing Ssytemchannel property

* PermissionOverwriteOptions can accept null as an option
(Why did no-one document this?)

src/structures/Webhook.js

@@ -247,7 +247,7 @@ class Webhook {
   /**
    * Edit the webhook.
    * @param {Object} options Options
-   * @param {string} [options.name] New name for this webhook
+   * @param {string} [options.name=this.name] New name for this webhook
    * @param {BufferResolvable} [options.avatar] New avatar for this webhook
    * @param {string} [reason] Reason for editing this webhook
    * @returns {Promise<Webhook>}