[Feature Request] Option to disable smooth scrolling

It'll be great to have an option to disable smooth scrolling. I honestly quite dislike smooth scrolling, and am sure many others feel the same way.

I see smooth scrolling is implemented in .

Here's a userscript to disable it for now:

```javascript
// ==UserScript==
// @name No Animation Markdown Preview
// @namespace Violentmonkey Scripts
// @match http://localhost:8642/*
// @grant none
// @version 1.0
// @author -
// @description 27/11/2023, 01:23:59
// ==/UserScript==

function main() {
const prevTo = TweenLite.to
TweenLite.to = function(target, duration, vars) {
prevTo(target, 0, vars)
}
}

main()
```