Make zooming steps smaller for trackpads

[RolandR]

Zooming should happen in smaller increments for trackpads as opposed to physical mouse wheels.

[funwithtriangles]

Unfortunately there is no easy way to detect whether a scroll event is coming from a mouse or a trackpad. My advice would be to simply reduce the sensitivity generally, as it's absolutely crazy with a touchpad (testing on Macbook Air M1).