fix transforming sortable items

[yonathan06]

I experienced an issue where sortable items with different heights were not transformed properly
The issue was that the delta was calculated as target.x - current.x (or target.y - current.y)
the delta was the diff between an item and the one before/after them, instead of the size of the dragged item
Changed it to transform based on the size of the dragged item

here is a reproduction repo https://stackblitz.com/edit/solidjs-templates-atuhev

[Terbiy]

@martinpengellyphillips, hi! Thank you for the library! Could you please merge this one so that dragging elements of different heights will work?

[Codisy1]

@martinpengellyphillips, hi! Thank you for the library! Could you please merge this one so that dragging elements of different heights will work?

This is really a very important part of the functionality.

[stanlrt]

@martinpengellyphillips Hi, is the library abandoned or is it deliberate to not implement new features that can already be built in userland with the existing version (which is a defendable position, bloat isnt great)?

[martinpengellyphillips]

@stanlrt - not abandoned, but I do open source for fun and so only work on my projects when the mood strikes me. The great thing about open source of course is you can fork it if you don't want to wait for me 😄