Support for undo of deeleted lines

[JoseConseco]

When I delete dd some lines, then undo the deletion

https://user-images.githubusercontent.com/13521338/131226102-ec77df67-e739-4588-8ed6-b4091710e5e2.mp4

footprint wont restore reverted lines color (they are marked as 'normal'). I assume it may be hard to implement. Awesome plugin btw! I have been waiting for something like this for long time.

EDIT: maybe instead of restoring the color, then undo should just mark the line as 100% new... could be easier to implement?