add embed support! (#894)

* add embed support!

* document message embeds

* make gawdl3y happy

* make edit great again

* make docs better

* Update Message.js

* Update TextBasedChannel.js

* Update TextBasedChannel.js

src/structures/Message.js

@@ -340,9 +340,16 @@ class Message {
     return this.mentions.users.has(data) || this.mentions.channels.has(data) || this.mentions.roles.has(data);
   }
 
+  /**
+   * Options that can be passed into editMessage
+   * @typedef {Object} MessageEditOptions
+   * @property {Object} [embed] An embed to be added/edited
+   */
+
   /**
    * Edit the content of the message
    * @param {StringResolvable} content The new content for the message
+   * @param {MessageEditOptions} [options={}] The options to provide
    * @returns {Promise<Message>}
    * @example
    * // update the content of a message
@@ -350,8 +357,8 @@ class Message {
    *  .then(msg => console.log(`Updated the content of a message from ${msg.author}`))
    *  .catch(console.error);
    */
-  edit(content) {
-    return this.client.rest.methods.updateMessage(this, content);
+  edit(content, options = {}) {
+    return this.client.rest.methods.updateMessage(this, content, options);
   }
 
   /**

src/structures/interface/TextBasedChannel.js

@@ -28,6 +28,8 @@ class TextBasedChannel {
    * @typedef {Object} MessageOptions
    * @property {boolean} [tts=false] Whether or not the message should be spoken aloud
    * @property {string} [nonce=''] The nonce for the message
+   * @property {Object} [embed] An embed for the message
+   * (see [here](https://discordapp.com/developers/docs/resources/channel#embed-object) for more details)
    * @property {boolean} [disableEveryone=this.client.options.disableEveryone] Whether or not @everyone and @here
    * should be replaced with plain-text
    * @property {boolean|SplitOptions} [split=false] Whether or not the message should be split into multiple messages if