minor fixes

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

@@ -256,7 +256,7 @@ For even values of `i`, the `continue` directive stops executing the body and pa
 ````smart header="The `continue` directive helps decrease nesting"
 A loop that shows odd values could look like this:
 
-```js
+```js run
 for (let i = 0; i < 10; i++) {
 
   if (i % 2) {

1-js/11-async/08-async-await/01-rewrite-async/task.md

@@ -15,6 +15,6 @@ function loadJson(url) {
     })
 }
 
-loadJson('no-such-user.json') // (3)
+loadJson('no-such-user.json')
   .catch(alert); // Error: 404
 ```

4-binary/02-text-decoder/article.md

@@ -58,7 +58,7 @@ alert( new TextDecoder().decode(binaryString) ); // Hello
 
 The syntax is:
 
-```js run
+```js
 let encoder = new TextEncoder();
 ```