Add `.Xresources` mouse cursor size

[ironhak]

When choosing mouse cursor size, it'll work for certain apps like firefox, but not for other. In my instance, using i3wm, the cursor has different size on firefox and thunar.

A quickfix was to:

Xcursor.size: 24

inside ~/.Xresources. I think nwg-look should append that by default to ensure consistency.

[nwg-piotr]

I don't test my stuff on X, but yes, it could be done. I'll try to remember, thank you.