Missing externs for String and DOMTokenList

/*
* Missing string externs.
* https://github.com/google/closure-compiler/blob/v20190106/externs/es5.js#L47
*/
String.prototype.trimStart = String.prototype.trimLeft;
String.prototype.trimEnd = String.prototype.trimRight;

/*
* Missing DOMTokenList externs.
* https://github.com/google/closure-compiler/blob/v20190106/externs/browser/html5.js#L3292
*/

/** @type {string} */
DOMTokenList.prototype.value;

/**
* @nosideeffects
* @return {!IteratorIterable>}
*/
DOMTokenList.prototype.entries = function () {};

/** @param {function(string, number, !IArrayLike)} callback */
DOMTokenList.prototype.forEach = function (callback) {};

/**
* @nosideeffects
* @return {!IteratorIterable}
*/
DOMTokenList.prototype.keys = function () {};