minor fixes

Author: iliakan

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

@@ -230,7 +230,9 @@ let rabbit = new Rabbit("White Rabbit", 10); // Error: this is not defined.
 
 Whoops! We've got an error. Now we can't create rabbits. What went wrong?
 
-The short answer is: constructors in inheriting classes must call `super(...)`, and (!) do it before using `this`.
+The short answer is:
+
+- **Constructors in inheriting classes must call `super(...)`, and (!) do it before using `this`.**
 
 ...But why? What's going on here? Indeed, the requirement seems strange.