Added Autumn Aurora 2 style crosshair to modding

Hi!

I really like your Stalker repo and only now noticed your site was hosted on git. I posted this tip on how to get the Autumn Aurora 2 crosshair in /sg/ a while ago and people seemed to like it, so I added it to your site. I also decided to include an image of what the crosshair looks like for those who have not played Autumn Aurora 2 as well.