Backporting, doc/bug fixes as well deprecation (#1826)

* Backporting, doc/bug fixes as well deprecation

* Adress issue with not resettable icons/images

src/structures/GroupDMChannel.js

@@ -119,7 +119,7 @@ class GroupDMChannel extends Channel {
   edit(data) {
     const _data = {};
     if (data.name) _data.name = data.name;
-    if (data.icon) _data.icon = data.icon;
+    if (typeof data.icon !== 'undefined') _data.icon = data.icon;
     return this.client.rest.methods.updateGroupDMChannel(this, _data);
   }
 
@@ -148,6 +148,7 @@ class GroupDMChannel extends Channel {
    * Add a user to the DM
    * @param {UserResolvable|string} accessTokenOrID Access token or user resolvable
    * @param {string} [nick] Permanent nickname to give the user (only available if a bot is creating the DM)
+   * @returns {Promise<GroupDMChannel>}
    */
 
   addUser(accessTokenOrID, nick) {
@@ -161,7 +162,7 @@ class GroupDMChannel extends Channel {
   /**
    * Set a new GroupDMChannel icon.
    * @param {Base64Resolvable|BufferResolvable} icon The new icon of the group dm
-   * @returns {Promise<Guild>}
+   * @returns {Promise<GroupDMChannel>}
    * @example
    * // Edit the group dm icon
    * channel.setIcon('./icon.png')
@@ -172,6 +173,25 @@ class GroupDMChannel extends Channel {
     return this.client.resolver.resolveImage(icon).then(data => this.edit({ icon: data }));
   }
 
+  /**
+   * Sets a new name for this Group DM.
+   * @param {string} name New name for this Group DM
+   * @returns {Promise<GroupDMChannel>}
+   */
+  setName(name) {
+    return this.edit({ name });
+  }
+
+  /**
+   * Removes an user from this Group DM.
+   * @param {UserResolvable} user User to remove
+   * @returns {Promise<GroupDMChannel>}
+   */
+  removeUser(user) {
+    const id = this.client.resolver.resolveUserID(user);
+    return this.client.rest.methods.removeUserFromGroupDM(this, id);
+  }
+
   /**
    * When concatenated with a string, this automatically concatenates the channel's name instead of the Channel object.
    * @returns {string}
@@ -203,6 +223,7 @@ class GroupDMChannel extends Channel {
   get typing() {}
   get typingCount() {}
   createCollector() {}
+  createMessageCollector() {}
   awaitMessages() {}
   // Doesn't work on Group DMs; bulkDelete() {}
   acknowledge() {}