Starting to work in an explicit Entry to track a deleted span from the
token tree, to be able to adjust the final token stream to close the gap.
WIP.
WIP
WIP. Formatting is tricky.
Progress on deleted lines. Need to track original lead and trail blank
lines though.
Tracking original gap between deleted span and following element,
formatting much better.
Major progress in line spacing, but mor tweaks still needed.
Add missing file.