Web updates

HTML 823f4bcb5a4d

Revise event listener removal in This change aligns the event listener removal behavior with implementations, specifically in two aspects: - The event handler's value should be set to null (i.e., deactivated). - Event listeners and handlers should be removed from the Window object as well. See prior investigation around deactivation of event handlers in #3836 and #3850. See investigation around's behavior in #3818. Tests:

Timothy Gu

SVG ad6fd97398b1

Fill in missing entries / sections in Changes appendix - Make sure there's a section for every chapter & appendix from SVG 1.1, and every one in SVG 2, and indicate which is which. - Put a list of all the major re-organizations in the "Editorial Changes" section at the top. - Added a few other missing changes, and corrected a few others. - Removed the testing links for the Linking chapter (still to be determined where/how best else to include this, but probably not here).

Amelia Bellamy-Royds