Remove 'mouseover' as synonym for 'mouseenter'

[ryanhamley]

Launch Checklist

• briefly describe the changes in this PR
  • removes duplicative mouseover event that says its a synonym for mouseenter
• manually test the debug page

Closes #7295

This looks like an oversight to me. The synonym was added in August 2017 8a68233 while the actual mouseover event was added in January 2018 35138df I'm guessing the synonym should have been removed at that time.

[ChrisLoer]

Although it shouldn't make any difference, we should probably clean up the duplicate entry here too, right?

mapbox-gl-js/src/ui/events.js

Lines 21 to 31 in a1233cb

	type: 'mousedown'
	| 'mouseup'
	| 'click'
	| 'dblclick'
	| 'mousemove'
	| 'mouseover'
	| 'mouseenter'
	| 'mouseleave'
	| 'mouseover'
	| 'mouseout'
	| 'contextmenu';

[ChrisLoer]

🚀 Thanks for cleaning this up!

[ryanhamley]

Oh wait...should this go to mb-pages rather than master?