Use new NSFW logic (#282)

* Use NSFW value returned by discord api

* Updated nsfw check

lib/structures/GuildChannel.js

@@ -49,6 +49,7 @@ class GuildChannel extends Channel {
         this.position = data.position !== undefined ? data.position : this.position;
         this.bitrate = data.bitrate !== undefined ? data.bitrate : this.bitrate;
         this.userLimit = data.user_limit !== undefined ? data.user_limit : this.userLimit;
+        this.nsfw = this.type !== 2 && ((this.name.length === 4 ? this.name === "nsfw" : this.name.startsWith("nsfw-")) || data.nsfw);
         if(data.permission_overwrites) {
             this.permissionOverwrites = new Collection(PermissionOverwrite);
             data.permission_overwrites.forEach((overwrite) => {
@@ -92,10 +93,6 @@ class GuildChannel extends Channel {
         return `<#${this.id}>`;
     }
 
-    get nsfw() {
-        return this.type !== 2 && (this.name.length === 4 ? this.name === "nsfw" : this.name.startsWith("nsfw-"));
-    }
-
     /**
     * Edit the channel's properties
     * @arg {Object} options The properties to edit