Add more code and comments regarding how single point elements adjust through undo history
Resolve TODOs
Comment tweak
Account for negative position in (TEXT . POSITION) undo element
undo-adjust-beg-end function
Revise comments
Merge branch 'undo-lazy-list' of https://github.com/epich/emacs into undo-lazy-list
End periods with double space, remove a comment from FIXME