Negative scroll multiplier not applied in vim

[atonyngo]

As of release version 0.13.2, negative scrolling multipliers in kitty.conf aren't applied properly in vim. I have narrowed the problem down locally to this merge.

For reference I am using a touchpad on a Dell XPS 9730 on Arch Linux. The reverse multiplier seems to be applied fine in other applications such as less. I also have both wheel_scroll_multiplier and touch_scroll_multiplier in my config both set to a negative value (-3).

[Luflosi]

This was my pull request #1263, which fixed #1257. Sorry, evidently I didn't think about negative multipliers. Multiplying s with -1 if OPT(wheel_scroll_multiplier) is less than 0 should fix this issue. @kovidgoyal can you think of a better fix? If not, I can make a pull request.

[kovidgoyal]

@Luflosi seems ok to me, go ahead.