docs(numberFilter): fix the description of the returned value

Closes angular#14408

Author: mcculley

src/ng/filter/filters.js

@@ -93,7 +93,9 @@ function currencyFilter($locale) {
  * @param {(number|string)=} fractionSize Number of decimal places to round the number to.
  * If this is not provided then the fraction size is computed from the current locale's number
  * formatting pattern. In the case of the default locale, it will be 3.
- * @returns {string} Number rounded to fractionSize and places a “,” after each third digit.
+ * @returns {string} Number rounded to `fractionSize` appropriately formatted based on the current
+ *                   locale (e.g., in the en_US locale it will have "." as the decimal separator and
+ *                   include "," group separators after each third digit).
  *
  * @example
    <example module="numberFilterExample">