Fix vararg docs in builtin JS String class docs.

 *

 *     String.fromCharCode(65,66,67)

 *

 * @param {Number} num1, ..., numN A sequence of numbers that are Unicode values.

 * @param {Number...} numbers A sequence of numbers that are Unicode values.

 * @return {String} String containing characters from encoding.

 */

/**

 * @method concat

 * Combines the text of two strings and returns a new string.

 *

 * `concat` combines the text from one or more strings and returns a new string. Changes to the text in

 * Combines combines the text from one or more strings and returns a new string. Changes to the text in

 * one string do not affect the other string.

 *

 * The following example combines strings into a new string.

 *     var hello = "Hello, ";

 *     console.log(hello.concat("Kevin", " have a nice day.")); // Hello, Kevin have a nice day.

 *

 * @param {String} string2...stringN

 * @param {String...} strings The strings to concatenate.

 * @return {String} Result of both strings.

 */