Fix Typo (#3524)

docs/docs/events.md

 |**params**|`unselectedTabIndex`: The index of the previously selected tab<br>`selectedTabIndex`: The index of the newly selected tab|
 
 ### buttonPressed event
-This event is emitted whenever a TopBat button is pressed by the user
+This event is emitted whenever a TopBar button is pressed by the user
 
 |Parameter|Description|
 |:-:|:--|