Avoid confusing prototype methods for static methods

Correct: `Array.from()` (it’s a static method)
Incorrect: `Array.join()` (doesn’t exist; it’s a prototype method)

This patch uses the common `#` syntax to denote `.prototype.`.

snippets/JSONtoCSV.md

@@ -2,9 +2,9 @@
 
 Converts an array of objects to a comma-separated values (CSV) string that contains only the `columns` specified.
 
-Use `Array.join(demiliter)` to combine all the names in `columns` to create the first row.
-Use `Array.map()` and `Array.reduce()` to create a row for each object, substituting non-existent values with empty strings and only mapping values in `columns`.
-Use `Array.join('\n')` to combine all rows into a string.
+Use `Array.prototype.join(demiliter)` to combine all the names in `columns` to create the first row.
+Use `Array.prototype.map()` and `Array.prototype.reduce()` to create a row for each object, substituting non-existent values with empty strings and only mapping values in `columns`.
+Use `Array.prototype.join('\n')` to combine all rows into a string.
 Omit the third argument, `delimiter`, to use a default delimiter of `,`.
 
 ```js