update: map return in a simple way

snippets/aperture.md

@@ -12,11 +12,11 @@ If `n` is greater than the length of `arr`, return an empty array.
 const aperture = (n, arr) =>
   n > arr.length
     ? []
-    : arr.slice(n - 1).map((v, i) => [...arr.slice(i, i + n - 1), v]);
+    : arr.slice(n - 1).map((v, i) => arr.slice(i, i + n));
 ```
 
 ```js
-R.aperture(2, [1, 2, 3, 4]); // [[1, 2], [2, 3], [3, 4]]
-R.aperture(3, [1, 2, 3, 4]); // [[1, 2, 3], [2, 3, 4]]
-R.aperture(5, [1, 2, 3, 4]); // []
+aperture(2, [1, 2, 3, 4]); // [[1, 2], [2, 3], [3, 4]]
+aperture(3, [1, 2, 3, 4]); // [[1, 2, 3], [2, 3, 4]]
+aperture(5, [1, 2, 3, 4]); // []
 ```