minor fixes

Author: iliakan

1-js/05-data-types/06-iterable/article.md

@@ -293,7 +293,7 @@ alert( str.slice(1, 3) ); // garbage (two pieces from different surrogate pairs)
 Objects that can be used in `for..of` are called *iterable*.
 
 - Technically, iterables must implement the method named `Symbol.iterator`.
-    - The result of `obj[Symbol.iterator]` is called an *iterator*. It handles the further iteration process.
+    - The result of `obj[Symbol.iterator]()` is called an *iterator*. It handles the further iteration process.
     - An iterator must have the method named `next()` that returns an object `{done: Boolean, value: any}`, here `done:true` denotes the end of the iteration process, otherwise the `value` is the next value.
 - The `Symbol.iterator` method is called automatically by `for..of`, but we also can do it directly.
 - Built-in iterables like strings or arrays, also implement `Symbol.iterator`.