refactor(Emoji): remove Guild#deleteEmoji in favour of Emoji#delete (#1877)

src/structures/Emoji.js

@@ -200,6 +200,16 @@ class Emoji extends Base {
     return this.requiresColons ? `<:${this.name}:${this.id}>` : this.name;
   }
 
+  /**
+   * Delete the emoji.
+   * @param {string} [reason] Reason for deleting the emoji
+   * @returns {Promise<Emoji>}
+   */
+  delete(reason) {
+    return this.client.api.guilds(this.guild.id).emojis(this.id).delete({ reason })
+      .then(() => this);
+  }
+
   /**
    * Whether this emoji is the same as another one.
    * @param {Emoji|Object} other The emoji to compare it to