Add `.ts` `.js` language toggle to code block

[babakfp]

Live Example

What is the benefit?

Not everyone uses, cares, or likes Typescript. Let's say I don't know ts, then the code is going to be very confusing, hard to read, and repulsive to me. I may even drop the Deno and go to the Node's big muscular sexy arms. What if?... What if the language toggle were available? Then I can just look at the code that I'm familiar with. Then probably I would stick with Deno (for now). It just makes the Deno so much hard for the beginners or the people that don't know ts. I believe it's a valuable move to add this feature. It's important not to forget to update both languages when editing the code block content.

Thanks.