Fixed small typo

2-ui / 2-events / 5-dispatch-events

In subchapter "Event constructor": first word use "Built-in" instead of "Build-in"

Author: RapTho

Diff for: 2-ui/2-events/05-dispatch-events/article.md

@@ -8,7 +8,7 @@ We can generate not only completely new events, that we invent for our own purpo
 
 ## Event constructor
 
-Build-in event classes form a hierarchy, similar to DOM element classes. The root is the built-in [Event](http://www.w3.org/TR/dom/#event) class.
+Built-in event classes form a hierarchy, similar to DOM element classes. The root is the built-in [Event](http://www.w3.org/TR/dom/#event) class.
 
 We can create `Event` objects like this: