This is currently broken on various corner cases and breaks the
"master branch should be good for day to day work" implicit rule,
ongoing work to stabilize this feature will take place on the
no-cursor-move-on-scroll branch until its deemed ready.
This reverts commit 1e38045d70.
Closes#4963
Kakoune now does not touch cursors when scrolling. It checks
if either the buffer or selections has been modified since
last redraw.
Fixes#4124Fixes#2844