minor fixes

1-js/02-first-steps/12-while-for/article.md

@@ -212,7 +212,7 @@ But we can force the exit at any time using the special `break` directive.
 
 For example, the loop below asks the user for a series of numbers, "breaking" when no number is entered:
 
-```js
+```js run
 let sum = 0;
 
 while (true) {

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

@@ -142,7 +142,7 @@ for (let char of str) {
 
 For deeper understanding let's see how to use an iterator explicitly.
 
-We'll iterate over a string in exactlly the same way as `for..of`, but with direct calls. This code creates a string iterator and gets values from it "manually":
+We'll iterate over a string in exactly the same way as `for..of`, but with direct calls. This code creates a string iterator and gets values from it "manually":
 
 ```js run
 let str = "Hello";
@@ -150,7 +150,9 @@ let str = "Hello";
 // does the same as
 // for (let char of str) alert(char);
 
+*!*
 let iterator = str[Symbol.iterator]();
+*/!*
 
 while (true) {
   let result = iterator.next();
@@ -268,7 +270,7 @@ for (let char of str) {
 alert(chars);
 ```
 
-...But is shorter.    
+...But it is shorter.    
 
 We can even build surrogate-aware `slice` on it:
 

1-js/09-classes/02-class-inheritance/article.md

@@ -40,7 +40,7 @@ The syntax to extend another class is: `class Child extends Parent`.
 
 Let's create `class Rabbit` that inherits from `Animal`:
 
-```js
+```js run
 *!*
 class Rabbit extends Animal {
 */!*

1-js/11-async/07-microtask-queue/article.md

@@ -56,7 +56,7 @@ Now the order is as intended.
 
 Remember the `unhandledrejection` event from the chapter <info:promise-error-handling>?
 
-Now we can see exactly how JavaScript finds out that there was an unhandled rejection
+Now we can see exactly how JavaScript finds out that there was an unhandled rejection.
 
 **"Unhandled rejection" occurs when a promise error is not handled at the end of the microtask queue.**
 

1-js/99-js-misc/01-proxy/article.md

@@ -310,7 +310,7 @@ user = new Proxy(user, {
     return {
       enumerable: true,
       configurable: true
-      /* ...other flags, probable "value:..."" */
+      /* ...other flags, probable "value:..." */
     };
   }