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/Guild.js

@@ -575,6 +575,7 @@ class Guild extends Base {
    * @property {number} [verificationLevel] The verification level of the guild
    * @property {number} [explicitContentFilter] The level of the explicit content filter
    * @property {ChannelResolvable} [afkChannel] The AFK channel of the guild
+   * @property {ChannelResolvable} [systemChannel] The system channel of the guild
    * @property {number} [afkTimeout] The AFK timeout of the guild
    * @property {Base64Resolvable} [icon] The icon of the guild
    * @property {GuildMemberResolvable} [owner] The owner of the guild
@@ -783,6 +784,7 @@ class Guild extends Base {
 
   /**
    * Allow direct messages from guild members.
+   * <warn>This is only available when using a user account.</warn>
    * @param {boolean} allow Whether to allow direct messages
    * @returns {Promise<Guild>}
    */
@@ -844,6 +846,7 @@ class Guild extends Base {
 
   /**
    * Prunes members from the guild based on how long they have been inactive.
+   * @param {Object} [options] Prune options
    * @param {number} [options.days=7] Number of days of inactivity required to kick
    * @param {boolean} [options.dry=false] Get number of users that will be kicked, without actually kicking them
    * @param {string} [options.reason] Reason for this prune
@@ -878,7 +881,7 @@ class Guild extends Base {
    * @typedef {Object} ChannelCreationOverwrites
    * @property {PermissionResolvable[]|number} [allow] The permissions to allow
    * @property {PermissionResolvable[]|number} [deny] The permissions to deny
-   * @property {RoleResolvable|UserResolvable} id ID of the group or member this overwrite is for
+   * @property {RoleResolvable|UserResolvable} id ID of the role or member this overwrite is for
    */
 
   /**
@@ -1052,7 +1055,7 @@ class Guild extends Base {
    * Delete an emoji.
    * @param {Emoji|string} emoji The emoji to delete
    * @param {string} [reason] Reason for deleting the emoji
-   * @returns {Promise}
+   * @returns {Promise<Emoji>}
    */
   deleteEmoji(emoji, reason) {
     if (!(emoji instanceof Emoji)) emoji = this.emojis.get(emoji);
@@ -1162,7 +1165,7 @@ class Guild extends Base {
 
   /**
    * Set the position of a role in this guild.
-   * @param {string|Role} role The role to edit, can be a role object or a role ID
+   * @param {RoleResolvable} role The role to edit, can be a role object or a role ID
    * @param {number} position The new position of the role
    * @param {boolean} [relative=false] Position Moves the role relative to its current position
    * @returns {Promise<Guild>}
@@ -1192,7 +1195,7 @@ class Guild extends Base {
 
   /**
    * Set the position of a channel in this guild.
-   * @param {string|GuildChannel} channel The channel to edit, can be a channel object or a channel ID
+   * @param {ChannelResolvable} channel The channel to edit, can be a channel object or a channel ID
    * @param {number} position The new position of the channel
    * @param {boolean} [relative=false] Position Moves the channel relative to its current position
    * @returns {Promise<Guild>}