add autofocus attribute to hex input

[safareli]

Most common thing to do when user is visiting this site is to focus on hex input and past in some color so why don't add autofocus attribute so next time it will be focused automatically

[imathis]

I think this might be useful for some, but I can't say this is the most common thing people want to do. I'll continue to consider it though. By the way the site has been completely rewritten on react and vite. Check it out: https://hslpicker.com