🚀 Feature

It would be great if there was a keyboard shortcut to scroll through slices of 3d images rather than having to use the mouse to drag the scroll bar or click the slide arrow.

Motivation

Occasionally I used napari to place points along structures in 3d space and this process would be much faster if I didn't need to move my mouse between dropping points and scrolling to the next slice.

Pitch

The ability to scroll through 3d images with the keyboard would be less tedious than using the mouse on the scroll bar. I don't think it matters which keys are used, arrow keys, WASD, +/-, anything else.

Alternatives

I am certain that a keyboard shortcut would make my job of annotating 3d images with points quicker.

Additional context

Additionally, a popup indicating which key scrolls through slices (like the feature here), would be even better.