scroller.coffee(performScroll): Fix `h` `l` horizontal scrolling
scroller.coffee(performScroll): Fix `h` `l` horizontal scrolling

When scrolling horizontally, `axisName` has value `"scrollLeft"`. Since
this line checks against value `"x"` it would always fail, causing `h`
and `l` to scroll vertically up and down respectively.

Use the `direction` argument in the condition instead, which is set to
`"x"` when scrolling horizontally with `h` and `l`.

This fixes horizontal scrolling using `h` and `l`.

smblott-github/vimium,gdh1995/vimium,poacher2k/vimium,decaffeinate-examples/vimium,philc/vimium,decaffeinate-examples/vimium,poacher2k/vimium,gdh1995/vimium,philc/vimium,smblott-github/vimium,philc/vimium,poacher2k/vimium,decaffeinate-examples/vimium,gdh1995/vimium,smblott-github/vimium