Update 18_3_conways_game_of_life.html

Remove superfluous `return`.

Author: deisner

code/solutions/18_3_conways_game_of_life.html

@@ -26,7 +26,7 @@
     return checkboxes.map(box => box.checked);
   }
   function checkboxesFromGrid(grid) {
-    return grid.forEach((value, i) => checkboxes[i].checked = value);
+    grid.forEach((value, i) => checkboxes[i].checked = value);
   }
   function randomGrid() {
     let result = [];