refactor(Util): make class extend null (#6000)

src/util/DataResolver.js

@@ -11,11 +11,7 @@ const Invite = require('../structures/Invite');
  * The DataResolver identifies different objects and tries to resolve a specific piece of information from them.
  * @private
  */
-class DataResolver {
-  constructor() {
-    throw new Error(`The ${this.constructor.name} class may not be instantiated.`);
-  }
-
+class DataResolver extends null {
   /**
    * Data that can be resolved to give an invite code. This can be:
    * * An invite code

src/util/SnowflakeUtil.js

@@ -9,11 +9,7 @@ let INCREMENT = 0;
 /**
  * A container for useful snowflake-related methods.
  */
-class SnowflakeUtil {
-  constructor() {
-    throw new Error(`The ${this.constructor.name} class may not be instantiated.`);
-  }
-
+class SnowflakeUtil extends null {
   /**
    * A Twitter snowflake, except the epoch is 2015-01-01T00:00:00.000Z
    * ```

src/util/Structures.js

@@ -31,11 +31,7 @@
 /**
  * Allows for the extension of built-in Discord.js structures that are instantiated by {@link BaseManager Managers}.
  */
-class Structures {
-  constructor() {
-    throw new Error(`The ${this.constructor.name} class may not be instantiated.`);
-  }
-
+class Structures extends null {
   /**
    * Retrieves a structure class.
    * @param {string} structure Name of the structure to retrieve

src/util/Util.js

@@ -10,11 +10,7 @@ const isObject = d => typeof d === 'object' && d !== null;
 /**
  * Contains various general-purpose utility methods.
  */
-class Util {
-  constructor() {
-    throw new Error(`The ${this.constructor.name} class may not be instantiated.`);
-  }
-
+class Util extends null {
   /**
    * Flatten an object. Any properties that are collections will get converted to an array of keys.
    * @param {Object} obj The object to flatten.