move nsfw to the new prop (#1687)

src/structures/TextChannel.js

@@ -25,6 +25,13 @@ class TextChannel extends GuildChannel {
      */
     this.topic = data.topic;
 
+    /**
+     * If the Discord considers this channel NSFW
+     * @type {boolean}
+     * @readonly
+     */
+    this.nsfw = data.nsfw;
+
     this.lastMessageID = data.last_message_id;
   }
 
@@ -43,15 +50,6 @@ class TextChannel extends GuildChannel {
     return members;
   }
 
-  /**
-   * If the Discord considers this channel NSFW
-   * @type {boolean}
-   * @readonly
-   */
-  get nsfw() {
-    return /^nsfw(-|$)/.test(this.name);
-  }
-
   /**
    * Fetch all webhooks for the channel.
    * @returns {Promise<Collection<Snowflake, Webhook>>}