Update SpectrumAnalyzer.cpp

Use this if u want :)
Ok, I see what you're doing here now, you're adding a column just for the f12 key, because it's not in this list. But, that's unnecessary. F11 and F12 are both right above backspace and the keys below it, so it seems incorrect to have an entire column that only lights when it reaches its maximum magnitude. And the F12 key isn't actually getting left out - if you look at line 109, any time the f11 key is lit, the f12 key also gets lit. And since you didn't remove that line there, I'm not sure this change really changes much.