Update formatting

snippets/formatDuration.md

@@ -10,7 +10,7 @@ Returns the human-readable format of the given number of milliseconds.
 - Divide `ms` with the appropriate values to obtain the appropriate values for `day`, `hour`, `minute`, `second` and `millisecond`.
 - Use `Object.entries()` with `Array.prototype.filter()` to keep only non-zero values.
 - Use `Array.prototype.map()` to create the string for each value, pluralizing appropriately.
-- Use `String.prototype.join(', ')` to combine the values into a string.
+- Use `String.prototype.join()` to combine the values into a string.
 
 ```js
 const formatDuration = ms => {