Update 'examples/higher-order-functions.jt'

examples/higher-order-functions.jt

@@ -3,7 +3,7 @@ import io
 // takes a function that receives two ints, returns an int
 // Func is the function type keyword, to not switch it with fn (which declares
 // a function)
-fn function_tester (Func function ([int, int] -> int)) -> int {
+fn function_tester (Func func ([int, int] -> int)) -> int {
     func(2, 2)
 }