Partials (#3070)

* Remove GroupDMChannels

they sparked no joy

* Start partials for message deletion

* MessageUpdate partials

* Add partials as an opt-in client option

* Add fetch() to Message

* Message.author should never be undefined

* Fix channels being the wrong type

* Allow fetching channels

* Refactor and add reaction add partials

* Reaction remove partials

* Check for emoji first

* fix message fetching

janky

* User partials in audit logs

* refactor overwrite code

* guild member partials

* partials as a whitelist

* document GuildMember#fetch

* fix: check whether a structure is a partial, not whether cache is true

* typings: Updated for latest commit (#3075)

* partials: fix messageUpdate behaviour (now "old" message can be partial)

* partials: add warnings and docs

* partials: add partials to index.yml

* partials: tighten "partial" definitions

* partials: fix embed-only messages counting as partials

src/structures/User.js

@@ -53,6 +53,8 @@ class User extends Base {
      */
     if (typeof data.avatar !== 'undefined') this.avatar = data.avatar;
 
+    if (typeof data.bot !== 'undefined') this.bot = Boolean(data.bot);
+
     /**
      * The locale of the user's client (ISO 639-1)
      * @type {?string}
@@ -73,6 +75,14 @@ class User extends Base {
     this.lastMessageChannelID = null;
   }
 
+  /**
+   * Whether this User is a partial
+   * @type {boolean}
+   */
+  get partial() {
+    return typeof this.username !== 'string';
+  }
+
   /**
    * The timestamp the user was created at
    * @type {number}
@@ -228,6 +238,14 @@ class User extends Base {
     return equal;
   }
 
+  /**
+   * Fetches this user.
+   * @returns {Promise<User>}
+   */
+  fetch() {
+    return this.client.users.fetch(this.id, true);
+  }
+
   /**
    * When concatenated with a string, this automatically returns the user's mention instead of the User object.
    * @returns {string}