feat(Webhook): add channel getter (#9074)

* fix: add channel property

* fix: missing new line

src/structures/Webhook.js

@@ -72,7 +72,7 @@ class Webhook {
 
     if ('channel_id' in data) {
       /**
-       * The channel the webhook belongs to
+       * The id of the channel the webhook belongs to
        * @type {Snowflake}
        */
       this.channelId = data.channel_id;
@@ -376,6 +376,15 @@ class Webhook {
       });
   }
 
+  /**
+   * The channel the webhook belongs to
+   * @type {?(TextChannel|VoiceChannel|NewsChannel|ForumChannel)}
+   * @readonly
+   */
+  get channel() {
+    return this.client.channels.resolve(this.channelId);
+  }
+
   /**
    * The timestamp the webhook was created at
    * @type {number}