Update toPercent docs with locale

src/utils/number.ts

@@ -5,6 +5,7 @@ function toLocaleStringSupportsOptions() {
 /**
  * Gets the value of a number formatted as a perentage.
  * @param {number} value The value as a number.
+ * @param {string} locale The locale to use for formatting (i.e. en-us).
  * @returns {string} The value formatted as a percentage.
  */
 export function toPercent(value: number | null | undefined, locale: string): string {