"log --graph --format=" learned that "%>|(N)" specifies the width
relative to the terminal's left edge, not relative to the area to
draw text that is to the right of the ancestry-graph section. It
also now accepts negative N that means the column limit is relative
to the right border.
* nd/graph-width-padded:
pretty.c: support <direction>|(<negative number>) forms
pretty: pass graph width to pretty formatting for use in '%>|(N)'