moving: prevent the cursor sticking on or skipping over overwide tabs
When we've landed on a tab and we are moving down and the tab starts
before the current chunk, then push the index forward -- otherwise we
would not advance. When instead we're moving up and the end of the
preceding row is on the same tab as the target column AND the end of
the current row is not on that same tab, then there is some character
on this row that we can put the cursor on, so push the index forward
-- otherwise we would skip a usable row.
This fixes https://savannah.gnu.org/bugs/?52125
and fixes https://savannah.gnu.org/bugs/?52139.
1 file changed