How do I unignore people on Steam?


Donkey Kong
I know this isn't relevant to the forum or the wiki, but I accidentally ignored a friend on Steam and need to know how to unignore him.
From the prompt that appears when you try to ignore someone:

"You can undo this by visiting their Steam Profile or unblocking them via your Friends list."
I blocked a friend who hasn't been on in like 2 years and got this drop-down menu by right-clicking his name:

Maybe you accidentally removed him from your friends list? Try re-adding him I suppose.
If you simply ignored the invite, then just ask him to send the invite again. Simple as that.