Add Wayland Scroll Factor

[mike-lloyd03]

Wayland users are reporting that mouse and trackpad scrolling is much too fast under Wayland.

#3142
#4455

Using @SuperSandro2000's recommendation here, I've added a config option to modify the scroll factor on Wayland (config.wayland_scroll_factor).

I've found that setting this value to 0.25 is ideal on my environment (Hyprland, Zellij).

I haven't modified the documentation yet because I wanted to see if this was a desirable approach first. I suppose it's possible to derive a suitable scroll factor from the window's scale factor, but I do not have enough familiarity with the Wayland protocol to implement this. If the config option route is acceptable, I will update the docs.

This also fixes a typo in CONTRIBUTING.md as proof that I actually read it.

[wez]

Thanks for diving in!

I'm a bit reticent to merge this because what I suspect is that there is something else going on in how the mouse scroll events are interpreted. This commit is certainly an easy fix but I think that it could eg: produce different results with different compositors, or when different devices are attached.

I think a little bit more research is needed. For example, are there other Rust wayland apps that scroll more reasonably? If so, what are they doing to process the scroll events?

[SuperSandro2000]

Not sure if that helps, but the only other program where I encountered similar behavior is VSCode but there you can manually specific the scroll factor.