Update ANSWERS.md

[simonsayscode]

From the MDN article on delete (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/delete):

delete is only effective on an object's properties. It has no effect on variable or function names.

While sometimes mis-characterized as global variables, assignments that don't specify an object (e.g. x = 5) are actually property assignments on the global object.

Updating the answers to properly reflect this.