Merge pull request #356 from 01-edu/correction-listat

correcting listat subject

subjects/listat.en.md

@@ -51,8 +51,8 @@ And its output :
 ```console
 student@ubuntu:~/[[ROOT]]/test$ go build
 student@ubuntu:~/[[ROOT]]/test$ ./test
-1
-how are
+you
+hello
 <nil>
 student@ubuntu:~/[[ROOT]]/test$
 ```

subjects/listforeachif.en.md

@@ -38,7 +38,7 @@ func IsPositive_node(node *NodeL) bool {
 func IsNegative_node(node *NodeL) bool {
 	switch node.Data.(type) {
 	case int, float32, float64, byte:
-		return node.Data.(int) > 0
+		return node.Data.(int) < 0
 	case string, rune:
 		return false
 	}