editor: Smooth scrolling

[marcocondrache]

Closes #4355

This is still a WIP, but it already works well. At 240 fps, it feels smooth like butter.

Ref: https://pavelfatin.com/scrolling-with-pleasure

Release Notes:

• Editor now supports smooth scrolling

[niekdomi]

Thanks for this PR, feels smooth. Are there any plans to integrate this into vim-mode as well?

(e.g., ctr-y, ctrl-e, ctrl-b, ctrl-f, ctrl-d, ctrl-u, zz, zt, zb)

or is this not part of this PR?

[marcocondrache]

@niekdomi yep, I still need to make the changes. I'm currently perfecting the scroll animation

[marcocondrache]

I agree this isn’t the ideal approach for animations, especially in the editor, since it causes the whole entity to re-render. That said, in practice it doesn’t seem to make a noticeable difference right now.

The current scrolling implementation in the editor already calls cx.notify() on every scroll event, so the animation isn’t doing anything fundamentally different in that regard. In fact, it may even be slightly more efficient, since we avoid updating the db and emitting events until the animation has finished, which is the opposite of how the current scroll handling works.

I’m very open to improving this if you think there’s a better direction, but wanted to share the reasoning behind the current approach