Fix typo

Author: cmontella

examples/tic-tac-toe.eve

@@ -30,7 +30,7 @@ commit
   [#cell board row: i column: j]
 ~~~
 
-A subtlety here is the last line, [#cell board row: i column: j]. Thanks to our relational semantics, this line actually generates all 9 cells. Since the sets of values computed in i and j have no relation to each other, when we use them together we get the cartesian product of their values. This means that if `i = {0, 1, 2}` and `j = {0, 1, 2}`, then `i x j = {(1, 1), (1, 2), ... (3, 2), (3, 3)}`. These are exactly the indices we need for our grid!
+A subtlety here is the last line, [#cell board row: i column: j]. Thanks to our relational semantics, this line actually generates all 9 cells. Since the sets of values computed in i and j have no relation to each other, when we use them together we get the cartesian product of their values. This means that if `i = {1, 2, 3}` and `j = {1, 2, 3}`, then `i x j = {(1, 1), (1, 2), ... (3, 2), (3, 3)}`. These are exactly the indices we need for our grid!
 
 Now we tag some special cell groupings: diagonal and anti-diagonal cells. The diagonal cells are `(1, 1)`, `(2, 2)`, and `(3, 3)`. From this we can see that diagonal cells have a row index equal to its column index