Update article.md

Replaced ":"s with ","s. 

I edited these lines before, and thought they were a little awkward w/ ":"s, but didn't see fit to change it then. But now ","s seem clearly better. Think of it as successive approximations.

Author: paroche

1-js/08-prototypes/04-prototype-methods/article.md

@@ -72,8 +72,8 @@ Why so?
 That's for historical reasons.
 
 - The `"prototype"` property of a constructor function works since very ancient times.
-- Later, in the year 2012: `Object.create` appeared in the standard. It gave the ability to create objects with a given prototype, but did not provide the ability to get/set it. So browsers implemented the non-standard `__proto__` accessor that allowed the user to get/set a prototype at any time.
-- Later, in the year 2015: `Object.setPrototypeOf` and `Object.getPrototypeOf` were added to the standard, to perform the same functionality as `__proto__`. As `__proto__` was de-facto implemented everywhere, it was kind-of deprecated and made its way to the Annex B of the standard, that is: optional for non-browser environments.
+- Later, in the year 2012, `Object.create` appeared in the standard. It gave the ability to create objects with a given prototype, but did not provide the ability to get/set it. So browsers implemented the non-standard `__proto__` accessor that allowed the user to get/set a prototype at any time.
+- Later, in the year 2015, `Object.setPrototypeOf` and `Object.getPrototypeOf` were added to the standard, to perform the same functionality as `__proto__`. As `__proto__` was de-facto implemented everywhere, it was kind-of deprecated and made its way to the Annex B of the standard, that is: optional for non-browser environments.
 
 As of now we have all these ways at our disposal.