fix bugs in parse-grid.sml update functions: exit loopX and loopY if coordinate is not in range of grid

fcore/parser/parse-grid.sml

@@ -11,7 +11,7 @@ struct
 
   local
     fun loopY (yAxis, x, ex, y, ey, colour) =
-      if y > ey then
+      if y > ey orelse y >= Vector.length yAxis then
         yAxis
       else
         let val yAxis = Vector.update (yAxis, y, colour)
@@ -19,7 +19,7 @@ struct
         end
 
     fun loopX (grid, x, ex, y, ey, colour) =
-      if x > ex then
+      if x > ex orelse x >= Vector.length grid then
         grid
       else
         let