Gagh! It'd be funny if it weren't so infuriating. I like spell-checking for English. It's really nice when you can't quite remember whether there is 1 'r' or 2 in "assurance", say. But after I've typed '`' (backquote) I don't want any help with screwing my code! I can screw it up on my own. Has any one else been irritated enough to figure this out already?
As described more fully in the linked answers, windows 8 includes a spell-checker that applies to all system-derived text-input widgets. But you can adjust the rules for a word by right-clicking on the word to bring up the context menu which includes a portion controlling the spell-checker.