I've made that mistake, and the inverse, often enough that I try to make sure to check I've written the correct word... and I still mess it up. Between the words being similar and the 'x' being right next to the 's' on US keyboard, it's bound to happen.

ON the flip side - when I (and I suspect many others) read Linux where Linus should be written, I rarely even notice and never really care because I've been there.

All this is a long winded way of saying: don't sweat it :) .