[dom] Incorrect link in createEvent definition

bzbarsky has just created a new issue for 
https://github.com/whatwg/dom:

== Incorrect link in createEvent definition ==
https://dom.spec.whatwg.org/#dom-document-createevent has the text:

    Let event be the result of invoking the initial value of 
constructor with the empty string as argument. 

where "invoking" is a link to 
https://dom.spec.whatwg.org/#concept-event-listener-invoke

But that's not the invoking happening here.

See https://github.com/whatwg/dom/issues/73