Make entry for jQuery.Event

[kswedberg]

Pull content from Event Object category in categories.xml

[tdelmas]

Additionally, the example only talks about these two syntax:

jQuery.Event( "click" )

and

jQuery.Event( "keydown", { keyCode: 64 } );

But the source says it may be used to "clone" an event:
https://github.com/jquery/jquery/blob/master/src/event.js#L523

jQuery.Event = function( src, props ) {
...
// Event object
if ( src && src.type ) {
	....
// Event type
} else {
	...
}

Example:

var new_event = jQuery.Event( old_event )

If it's not reserved for internal use, it should be documented too.