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/digitize.md

@@ -3,7 +3,7 @@
 Converts a number to an array of digits.
 
 Convert the number to a string, using the spread operator (`...`) to build an array.
-Use `Array.map()` and `parseInt()` to transform each value to an integer.
+Use `Array.prototype.map()` and `parseInt()` to transform each value to an integer.
 
 ```js
 const digitize = n => [...`${n}`].map(i => parseInt(i));