Replaced every instance of which with the respective button
Replaced every instance of which with the respective button

For reference
https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/which
https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/button
CanisLupus/swift-selection-search,CanisLupus/swift-selection-search,CanisLupus/swift-selection-search