Fixed a minor typo in commented code

Just a small update fixing an issue that I think may have been tripping some people up.

Posts Array in the script.js file comes with some example lines for adding more posts. However, the first line was missing a comma at the end, causing the array to break if you actually uncomment it. Each entry in a JavaScript array should be separated by a comma. Now it correctly reads as follows:

let postsArray = [
//[ "posts/2020-11-10-Special-Characters-Example.html", encodeURI( 'Spéci@l "Character\'s" Examp|e' ) ],
//[ "posts/2020-11-10-My-Third-Post-Example.html" ],
//[ "posts/2020-11-10-My-Second-Post-Example.html" ],
[ "posts/2020-11-10-Post-Template.html" ] ];

Happy blogging!