Implement platform specific scroll speed

[AndreasArvidsson]

On the community backlog session we agreed that it does not make sense to include an arbitrary divider here. This setting is already specific to the continuous scroll amount. We should make sure when we pick a new default (or perhaps a platform specific default) that it scrolls approximately the same amount across platforms — potentially adding settings_mac.talon, etc.

Originally posted by @nriley in #1605 (comment)

[FireChickenProductivity]

Halving the scrolling speed on Mac seemed to get about the same result as the standard scrolling speed on windows. I did the following experiment on a windows 10 machine and my Mac: I opened VSCode zoomed in enough that about 24 lines were showing and tried scrolling down. On windows, that scrolled down 2 lines. I got it to scroll about 2 lines down on Mac after halving the speed.

[lunixbochs]

this might depend on what the user has set for their scroll speed at the OS level

[FireChickenProductivity]

On my Mac, changing the scroll speed does not change the effect of scrolling commands.