Fix asterisk widths on columns tweak

This is a tweak for #1927. Subtracting the auto width(s) from the leftoverWidth reduces the width of oneAsterisk if there is more than one column. i.e. leftoverWidth = 400, the first gets 200 (400/2) and the second gets 100 (200/2). Instead, I add up the autoWidths, then subtract that from leftoverWidth before doling out the extra.